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Sample records for 218po 214pb 214bi

  1. Diurnal variations of (218)Po, (214)Pb, and (214)Po and their effect on atmospheric electrical conductivity in the lower atmosphere at Mysore city, Karnataka State, India.

    PubMed

    Pruthvi Rani, K S; Paramesh, L; Chandrashekara, M S

    2014-12-01

    The short-lived radon daughters ((218)Po, (214)Pb, (214)Bi and (214)Po) are natural tracers in the troposphere, in particular near the ground surface. They are electrically charged particles and are chemically reactive. As soon as they are formed they get attached to the aerosol particles of the atmosphere. The behavior of radon daughters is similar to that of aerosols with respect to their growth, transport and removal processes in the atmosphere. The electrical conductivity of the atmosphere is mainly due to the presence of highly mobile ions. Galactic cosmic rays are the main source of ionization in the planetary boundary layer; however, near the surface of the earth, ions are produced mainly by decays of natural radioactive gases emanating from the soil surface and by radiations emitted directly from the surface. Hence the electrical conductivity of air near the surface of the earth is mainly due to radiations emitted by (222)Rn, (218)Po, (214)Pb, (214)Bi and (214)Po, and depends on aerosol concentrations and meteorological parameters. In the present work the diurnal and seasonal variations of radon and its progeny concentrations are studied using Low Level Radon Detection System and Airflow Meter respectively. Atmospheric electrical conductivity of both positive and negative polarities is measured using a Gerdien Condenser. All the measurements were carried out simultaneously at one location in Mysore city (12°N, 76°E), India. The diurnal variation of atmospheric electrical conductivity was found to be similar to that of ion pair production rate estimated from radon and its progeny concentrations with a maximum in the early morning hours and minimum during day time. The annual average concentrations of (222)Rn, (218)Po, (214)Pb, and (214)Po at the study location were found to be 21.46, 10.88, 1.78 and 1.80 Bq m(-3) respectively. The annual average values of positive and negative atmospheric electrical conductivity were found to be 18.1 and 16.6 f S m(-1

  2. Spectroscopy of 214Bi and systematics of 210,212,214Pb(0+) long->β-210,212,214Bi(0-)

    NASA Astrophysics Data System (ADS)

    Berant, Z.; Schuhmann, R. B.; Alburger, D. E.; Chou, W. T.; Gill, R. L.; Warburton, E. K.; Wesselborg, C.

    1991-04-01

    Experiments designed to provide more information on the spectroscopy of 214Bi, and on 214Pb(β-)214Bi in particular, were undertaken because of interest in first-forbidden β decay in the lead region. The experiments consisted of γ-γ coincidences and angular correlations, conversion electron measurements, level lifetime determinations, and precision γ-ray energy measurements. The 352-keV level of 214Bi was found to be a strong candidate (and the only candidate) for the 0-1 state. Recent additions to the 214Pb decay scheme are confirmed by γ-γ coincidence measurements. A careful evaluation of the 214Bi level scheme is made with emphasis on separating experimentally based conclusions from speculations based on systematics and other ``weak'' arguments. Shell-model calculations of the spectroscopy of 210,212Bi and 210,212Pb(β-)210,212Bi were performed using a modification of the Kuo-Herling realistic interaction. These calculations and a generalized seniority model provide a basis for an examination of the systematics of the A=210, 212, 214 spectroscopy and β decay. The generalized seniority model is found to be a quite good approximation which provides a quantitative understanding of the 214Pb decay rates.

  3. Radon daughter carousel: An automated instrument for measuring indoor concentrations of 218Po, 214Pb, and 214Bi

    NASA Astrophysics Data System (ADS)

    Nazaroff, William W.

    1983-09-01

    A microprocessor-controlled instrument for measuring the concentrations of radon progeny in indoor air is described. The measurement technique is based on alpha spectroscopy and uses two counting intervals following a sampling period during which radon progeny are collected on a filter. The counting intervals are selected to provide optimal precision for measuring 222Rn progeny for fixed total measurement times ranging from 30 to 60 min: concentrations as low as 0.5 pCi/1 can be measured with less than 20% uncertainty in 45 min. The instrument can also be used to estimate the potential alpha energy concentration of 220Rn decay products. The device operates under the control of a computer or a data terminal and functions for week-long periods between filter changes. The user can specify the sampling- and counting-interval timing over a wide range and select from among several operating modes. A number of performance tests are also described indicating that for typical indoor concentrations the measurement uncertainty is dominated by counting statistics.

  4. Aerodynamic size associations of 212Pb and 214Pb in ambient aerosols.

    PubMed

    Papastefanou, C; Bondietti, E A

    1987-11-01

    The aerodynamic size distributions of short-lived Rn daughters (reported as 214Pb and 212Pb) in ambient aerosol particles were measured using low-pressure as well as conventional low-volume and high-volume impactors. The activity distribution of 214Pb and 212Pb, measured by alpha spectroscopy, was largely associated with submicron aerosols in the accumulation mode (0.08 to 2 microns). The activity median aerodynamic diameter ranged from 0.09 to 0.37 micron (mean 0.16 micron) for 214Pb and from 0.07 to 0.25 micron (mean 0.13 micron) for 212Pb. The mean values of the geometric standard deviation (sigma g) were 2.97 and 2.86, respectively. By comparison, the median diameters of cosmogenic 7Be and ambient SO4(2-) were about 0.24 micron higher. In almost 70% of the low-pressure impactor measurements, the activity distribution of 214Pb showed a small shift to larger particle sizes relative to 212Pb. This shift probably results from alpha-recoil detachment of parent 218Po, which preferentially depletes 214Pb from smaller particles. The subsequent recondensation of 214Pb causes an enrichment of larger aerosols. Early morning and afternoon measurements indicated that similar size associations of 214Pb occur, despite humidity differences and the potential for fresh particle production in the afternoon. Health physics implications of the results are also discussed. PMID:3667271

  5. Measurement of airborne {sup 218}Po - A Bayesian approach

    SciTech Connect

    Groer, P.G.; Lo, Y.

    1996-12-01

    The standard mathematical treatment of the buildup and decay of airborne radionuclides on a filter paper uses the solutions of the so-called bateman equations adapted to the sampling process. The equations can be interpreted as differential equations for the expectation of an underlying stochastic process, which describes the random fluctuations in the accumulation and decay of the sampled radioactive atoms. The process for the buildup and decay of airborne {sup 218}Po can be characterized as an {open_quotes}immigration-death process{close_quotes} in the widely adopted, biologically based jargon. The probability distribution for the number of {sup 218}Po atoms, accumulated after sampling time t, is Poisson. We show that the distribution of the number of counts, registered by a detector with efficiency {epsilon} during a counting period T after the end of sampling, it also Poisson, with mean dependent on {epsilon},t,T, the flowrate and N{sub o}, the number of airborne {sup 218}Po atoms per unit volume. This Poisson distribution was used to construct the likelihood given the observed number of counts. After inversion with Bayes` Theorem we obtained the posterior density for N{sub o}. This density characterizes the remaining uncertainty about the measured under of {sup 218}Po atoms per unit volume of air. 6 refs., 3 figs., 1 tab.

  6. Measurement of airborne 218Po--a Bayesian approach.

    PubMed

    Groer, P G; Lo, Y

    1996-12-01

    The standard mathematical treatment of the buildup and decay of airborne radionuclides on a filter paper uses the solutions of the so-called Bateman equations adapted to the sampling process. These equations can be interpreted as differential equations for the expectation of an underlying stochastic process, which describes the random fluctuations in the accumulation and decay of the sampled radioactive atoms. The process for the buildup and decay of airborne 218Po can be characterized as an "immigration-death process" in the widely adopted, biologically based jargon. The probability distribution for the number of 218Po atoms, accumulated after sampling time t, is Poisson. We show that the distribution of the number of counts, registered by a detector with efficiency epsilon during a counting period T after the end of sampling, is also Poisson, with mean dependent on epsilon, t, T, the flowrate and N(o), the number of airborne 218Po atoms per unit volume. This Poisson distribution was used to construct the likelihood given the observed number of counts. After inversion with Bayes' Theorem we obtained the posterior density for N(o). This density characterizes the remaining uncertainty about the measured number of 218Po atoms per unit volume of air. PMID:8919080

  7. The behaviour of short-lived radiogenic lead isotopes ( 214Pb and 212Pb) in groundwaters and laboratory leaching experiments

    NASA Astrophysics Data System (ADS)

    Hussain, N.; Krishnaswami, S.

    1982-05-01

    The concentrations of 214Pb ( half-life=26.4minutes) and 22Rn ( half-life=3.84days) have been measured in deep groundwaters of Gujarat, India. The results show that the abundance of 214Pb in the water is only ˜25% of that expected from its production through the radioactive decay of dissolved 222Rn. This deficiency if modelled in terms of a first-order removal, yields a residence time of ˜10 minutes for 214Pb in these waters. The estimated residence time for 214Pb is the shortest observed for any nuclide in natural water systems and suggests that reactive nuclides lead like could be removed from aqueous phases to adjoining solid surfaces on extremely short time scales. Results of laboratory experiments using the 212Pb- 224Ra pair are compatible with the observed fast removal of 214Pb from groundwaters. Re-evaluation of 234Th residence times in these waters using a model with a recoil flux of 234Th into aqueous phase, the same as that of 222Rn, yields values in the range of 23 to <176 minutes, very similar to that of 214Pb. This "concordancy" in the residence times seems to suggest that the geochemical behaviour of 234Th and 214Pb in these waters is quite similar.

  8. Temporal variation of 212Pb concentration in outdoor air of Milan and a comparison with 214Bi.

    PubMed

    Marcazzan, G M; Caprioli, E; Valli, G; Vecchi, R

    2003-01-01

    Continuous measurement of hourly concentrations of 212Pb attached to aerosol particles was carried out during the whole year 2000 in the outdoor air of Milan (Italy). An improved experimental method based on on-line alpha spectroscopy during atmospheric particulate matter sampling allowed the contemporary determination of 212Pb and 214Bi through the deconvolution of the alpha energy spectral distribution analysis. The 212Pb hourly concentrations were about 100 times lower than 214Bi but showed a similar characteristic diurnal time trend. However, the influence of meteorological parameters such as rain and wind was more evident in 212Pb than in 214Bi concentrations. The 212Pb average annual concentration was 0.090 +/- 0.060 Bq/m3 with daily mean concentration varying from 0.013 to 0.333 Bq/m3. PMID:12683729

  9. Numerical Investigations of the Deposition of Unattached {sup 218}Po and {sup 212}Pb from Natural Convection Enclosure Flow

    SciTech Connect

    Nazaroff, W.W.; Kong, D.; Gadgil, A.J.

    1992-02-01

    We report numerical predictions of the deposition to enclosure surfaces of unattached {sup 218}Po and {sup 212}Pb, short-lived decay products of {sup 222}Rn and {sup 220}Rn, respectively. The simulations are conducted for square and rectangular two-dimensional enclosures under laminar natural convection flow with Grashof numbers in the range 7 x 10{sup 7} to 8 x 10{sup 10}. The predictions are based upon a finite-difference natural-convection fluid-mechanics model that has been extended to simulate the behavior of indoor radon decay products. In the absence of airborne particles, the deposition velocity averaged over the enclosure surface was found to be in the range (2-4) x 10{sup -4} m s{sup -1} for {sup 218}Po and (1-3) x 10{sup -4} m s{sup -1} for {sup 212}Pb. In each simulation, the deposition rate varied by more than an order of magnitude around the surface of the enclosure with the largest rates occurring near corners. Attachment of decay products to airborne particles increased the deposition velocity; for example, attachment of {sup 218}Po at a rate of 50 h{sup -1} increased the predicted average deposition velocity by 30-70% over values in the absence of attachment. The simulation results have significance for assessing the health risk associated with indoor exposure to {sup 222}Rn and {sup 220}Rn decay products and for investigating the more general problem of the interaction of air pollutants with indoor surfaces.

  10. Analysis of the saturation phenomena of the neutralization rate of positively charged 218Po in water vapor.

    PubMed

    Tan, Yanliang; Xiao, Detao; Shan, Jian; Zhou, Qingzhi; Qu, Jingnian

    2014-09-01

    Generally, 88% of the freshly generated 218Po ions decayed from 222Rn are positively charged. These positive ions become neutralized by recombination with negative ions, and the main source of the negative ions is the OH- ions formed by radiolysis of water vapor. However, the neutralization rate of positively charged 218Po versus the square root of the concentration of H2O will be a constant when the concentration of H2O is sufficiently high. Since the electron affinity of the hydroxyl radical formed by water vapor is high, the authors propose that the hydroxyl radical can grab an electron to become OH-. Because the average period of collision with other positively charged ions and the average life of the OH- are much longer than those of the electron, the average concentration of negative ions will grow when the water vapor concentration increases. The authors obtained a model to describe the growth of OH- ions. From this model, it was found that the maximum value of the OH- ion concentration is limited by the square root of the radon concentration. If the radon concentration is invariant, the OH- ion concentration should be approximately a constant when the water vapor concentration is higher than a certain value. The phenomenon that the neutralization rate of positively charged 218Po versus the square root of the water vapor concentration will be saturated when the water vapor concentration is sufficiently high can be explained by this mechanism. This mechanism can be used also to explain the phenomenon that the detection efficiency of a radon monitor based on the electrostatic collection method seems to be constant when the water vapor concentration is high. PMID:25068963

  11. Measurement of liquid scintillation sources of (210)Pb obtained from (222)Rn decay.

    PubMed

    Antohe, A; Sahagia, M; Luca, A; Ioan, M-R; Ivan, C

    2016-03-01

    Liquid scintillation samples were filled with (222)Rn and the activity was measured with good precision after reaching the secular equilibrium with the progeny (218)Po, (214)Pb, (214)Bi and (214)Po. After decay of most of (222)Rn activity, the samples contain (210)Pb and progeny. The activities of (210)Pb and progeny can be calculated as a function of time using the initial (222)Rn activity. The samples were measured in a TDCR counter and the experimentally determined counting efficiencies are in accordance with previously published results. PMID:26725538

  12. Description of the properties of unattached 218Po and 212Pb particles by means of the classical theory of cluster formation.

    PubMed

    Raes, F

    1985-12-01

    A review is given of the classical theory of cluster formation to see whether it is a useful description of the behaviour of unattached radioactive particles. Special attention is given to the predictions concerning the size of the clusters, their growth, and their dependency on humidity and other trace gases. The theory is compared with the experimental observations of the last two decades. It is found that the theory predicts most of the properties of 218Po and 212Pb particles. It cannot explain the conflicting results regarding the humidity dependency of the unattached particle size. An important prediction of the theory is the failure of the unattached particle concept in some environmental conditions. PMID:4077520

  13. Hawking's A Briefer History of Time's No-God-Universe disproven by primordial ^218Po halos embedded in granite rocks, which proves their rapid creation due to ^218Po's 3 min t1/2, something only the God of Genesis could have done

    NASA Astrophysics Data System (ADS)

    Gentry, Robert

    2011-04-01

    Quotes from my Science (184, 62, 1974) report, Radiohalos in Radiochronological and Cosmological Perspective, show why primordial polonium halos earlier commanded attention for creation," It is also apparent that Po halos do pose contradictions to currently held views of Earth history" "For example, there is first the problem of how isotopic separation of several Po isotopes [or their β-decay precursors could have occurred naturally. Second, a straightforward explanation of ^218Po halos implies that the 1-μm radiocenters of very dark halos of this type initially contained as many as 5 x 10^9 atoms (a concentration of more than 50 percent) of the isotope ^218Po (half-life, 3 minutes), a problem that almost defies reason. A further necessary consequence, that such Po halos could have formed only if the host rocks underwent a rapid crystallization, renders exceedingly difficult, in my estimation, the prospect of explaining these halos by physical laws as presently understood." In 1977 E. P. Wigner, G. N. Flerov (Dubna), Ed Anders, E. Segre, F. Dyson, and John Wheeler all commented on these results (see alphacosmos.net). Also, ^14N detection in dwarf radiohalos may be of cosmological significance in implying a superheavy element origin from ^14C emission.

  14. Some observations on the concentrations of short-lived decay products of radon and thoron in the monsoon rains of Bombay, India

    NASA Astrophysics Data System (ADS)

    Rangarajan, C.; Eapen, C. D.

    1985-08-01

    The concentrations of radon decay products 214Pb(RaB) and 214Bi(RaC) and thoron daughter 212Pb(ThB) have been measured in rainfall at Bombay. The presence of short-lived 218Po(RaA) is indicated in a few samples. The levels of 214Pb varied from 300 to 7000 pCi (11-260 Bq) per liter, while the activity ratios of 214Bi/214Pb are in the range of 0.5-1.5. From these values of the ratios a cloud drop lifetime, from nucleation to deposition, of 20-60 min is estimated. The concentrations of 212Pb varied from 2 to 30 pCi (0.075-1.1 Bq) per liter. The levels of radon and thoron daughter products are lower in Bombay summer rainfall compared with other areas due to their reduced concentrations in the maritime monsoon winds. Approximate estimates of scavenging ratios based on the surface air concentrations are 85±65 (1 standard deviation) and 30±20 (1 standard deviation) for radon and thoron daughters, respectively.

  15. Abundance of low-energy gamma rays in the decay of 238U, 234U, 230Th, 227Ac, 226Ra and 214Pb

    NASA Astrophysics Data System (ADS)

    Komura, K.; Yamamoto, M.; Ueno, K.

    1990-11-01

    Abundance of low-energy gamma rays emitted from 238U (49.5 keV), 227Ac (50.0 keV), 234U (53.2 keV), 214Pb (53.2 keV), 230Th (67.7 and 143.9 keV) and 226Ra (186 keV) was determined using a high-purity Ge low energy photon spectrometer. The results are: 49.5 keV (238U): 0.059±0.002%, 50.0 keV (227Ac): 8.18±0.17%, 53.2 keV (234U): 0.156±0.006%, 53.2 keV (214Pb): 0.927±0.025%, 67.7 keV (230Th): 0.463±0.012%, 143.9 keV (230Th): 0.078±0.007%, 186.0 keV (226Ra): 3.688±0.099%.

  16. A study on natural radiation exposure in different realistic living rooms.

    PubMed

    El-Hussein, A

    2005-01-01

    In the first part of the paper, the factors affecting 222Rn properties in 25 different realistic living rooms (with low ventilation rates) of different houses in El-Minia City (Upper Egypt) have been studied; they included the activity concentration of 222Rn gas (C(o)), the unattached fraction (f(p)) of 218Po and 214Pb, the unattached potential alpha energy concentration (PAEC) and the equilibrium factor (F). The activity distributions of unattached 218Po and 214Pb as well as for the PAEC were determined. With a dosimetric model calculation [ICRP, 1994b. Human Respiratory Tract Model For Radiological Protection. Pergamon Press, Oxford. ICRP Publication 66] the total deposition fraction of unattached 218Po and 214Pb in human respiratory tract was evaluated to determine the total equivalent dose. An electrostatic precipitation method and a wire screen diffusion battery technique were both employed for the determination of 222Rn gas concentration and its unattached decay products, respectively. The mean activity concentration of 222Rn gas (C(o)) was found to be 110+/-20 Bq m(-3). The mean unattached activity concentrations of 218Po and 214Pb were found to be 0.6 and 0.35 Bq m(-3), respectively. A mean unattached fraction (f(p)) of 0.09+/-0.01 was obtained at a mean aerosol particle concentration (Z) of (2.9+/-0.23) x 10(3)cm(-3). The mean equilibrium factor (F) was determined to be 0.31+/-0.02. The mean PAEC of unattached 218Po and 214Pb was found to be 8.74+/-2.1 Bq m(-3). The activity distributions of 218Po and 214Pb show mean activity median diameters (AMD) of 1.5 and 1.85 nm with mean geometric standard deviations (SD) of 1.33 and 1.45, respectively. The mean activity distribution of the PAEC shows an AMD of 1.65 nm with a geometric standard deviation of 1.25. At a total deposition fraction of about 97% the total equivalent dose to the lung was determined to be about 133 microSv. The second part of this paper deals with a study of natural radionuclide contents of

  17. A comparison of measurements of thoron, radon and their daughters in a test house with model predictions

    NASA Astrophysics Data System (ADS)

    Zarcone, M. J.; Schery, S. D.; Wilkening, M. H.; McNamee, E.

    Airborne thoron ( 220Rn), radon ( 222Rn), 212Bi, 212Pb, 218Po, 214Bi and 214Pb have been measured in a one-story test house at various periods over four seasons. Auxiliary measurements were made of meteorological variables, ventilation rates, flux density from soil and building materials, and aerosol concentration. Time dependent results indicate significant changes in radon, and the daughters of radon and thoron, in response to meteorological conditions. In comparison, thoron was relatively more stable. Measurements for time-dependent behavior and average disequilibrium ratios seem in reasonable agreement with predictions for a model for indoor radioactivity that uses first-order sink and source terms. The major source for both thoron and radon appears to be the soil.

  18. Measurements of airborne 212Pb and 220Rn at varied indoor locations within the United States.

    PubMed

    Schery, S D

    1985-12-01

    Measurements have been made at varied locations within the United States comparing the concentration of 212Pb in air with that of the progeny of 222Rn to see if 212Pb is typically a significant contributor to indoor radioactivity. Auxiliary measurements were made comparing 220Rn with 222Rn. In terms of potential alpha-particle energy, 212Pb is significant (the ratio of its contribution to the combined contribution of 218Po, 214Pb, and 214Bi averaged about 0.6) and may warrant greater consideration as a component of indoor radioactivity. Correlations were found between the concentration of 220Rn progeny and 222Rn progeny, and the concentration of 220Rn and 222Rn. Environmental factors such as transport pathways and ventilation rates which exert a common influence on the concentrations of airborne isotopes provide a possible explanation for these correlations. PMID:4077512

  19. Nanoaerosols Including Radon Decay Products in Outdoor and Indoor Air at a Suburban Site

    PubMed Central

    Smerajec, Mateja; Vaupotič, Janja

    2012-01-01

    Nanoaerosols have been monitored inside a kitchen and in the courtyard of a suburban farmhouse. Total number concentration and number size distribution (5–1000 nm) of general aerosol particles, as measured with a Grimm Aerosol SMPS+C 5.400 instrument outdoors, were mainly influenced by solar radiation and use of farming equipment, while, indoors, they were drastically changed by human activity in the kitchen. In contrast, activity concentrations of the short-lived radon decay products 218Po, 214Pb, and 214Bi, both those attached to aerosol particles and those not attached, measured with a Sarad EQF3020-2 device, did not appear to be dependent on these activities, except on opening and closing of the kitchen window. Neither did a large increase in concentration of aerosol particles smaller than 10 or 20 nm, with which the unattached radon products are associated, augment the fraction of the unattached decay products significantly. PMID:22523488

  20. Surface deposition of 222Rn decay products with and without enhanced air motion.

    PubMed

    Rudnick, S N; Maher, E F

    1986-09-01

    The effectiveness of fan-induced air motion in reducing airborne activities of short-lived 222Rn decay products was evaluated in a 78.5-m3 chamber. Observed reductions were as high as 50% for 218Po (RaA), 79% for 214Pb (RaB), and 86% for 214Bi (RaC). Activity measurements of these nuclides on chamber and fan surfaces, along with airborne activities, were used to calculate material balances. Greater than about 90% of deposited activity was found on chamber surfaces, although areal activity densities were higher on fan surfaces. Deposition velocities for decay products not attached to particles were 2.3 mm s-1 when no fans were in operation and 9.2 to 13 mm s-1 when fans were used. Mean boundary layer thicknesses for unattached decay products were estimated to be about four times the recoil distance of a 214Pb atom when no fans were used and about equal to the recoil distance when fans were used. PMID:3744829

  1. Surface deposition of 222Rn decay products with and without enhanced air motion

    SciTech Connect

    Rudnick, S.N.; Maher, E.F.

    1986-09-01

    The effectiveness of fan-induced air motion in reducing airborne activities of short-lived /sup 222/Rn decay products was evaluated in a 78.5-m3 chamber. Observed reductions were as high as 50% for 218Po (RaA), 79% for /sup 214/Pb (RaB), and 86% for /sup 214/Bi (RaC). Activity measurements of these nuclides on chamber and fan surfaces, along with airborne activities, were used to calculate material balances. Greater than about 90% of deposited activity was found on chamber surfaces, although areal activity densities were higher on fan surfaces. Deposition velocities for decay products not attached to particles were 2.3 mm s-1 when no fans were in operation and 9.2 to 13 mm s-1 when fans were used. Mean boundary layer thicknesses for unattached decay products were estimated to be about four times the recoil distance of a /sup 214/Pb atom when no fans were used and about equal to the recoil distance when fans were used.

  2. Half-life of /sup 218/Po

    SciTech Connect

    Potapov, V.G.; Soloshenkov, P.S.

    1986-10-01

    The decay of Po 218 is accompanied by the emission of 6.00-MeV alpha particles. The most suitable method for studying it is the alphaspectrometric method. To generate radon, the source for RaA, the authors used a preparation of Ra 226 with a high degree of purity. Targets were prepared for measuring the half-life on a radon setup. Approximately 30 sec after holding in a radon atmosphere the target was placed with the polonium deposited on it into a vacuum chamber. It was noted that the intensity of the peak at 6.70 MeV decreases at the same rate as the decay of Po 218, and the ratio of the intensities of their peaks was equal to 0.037 +/- 0.007%. The spectra (alpha was analyzed on an LP-4900 analyzer. The values of the half-life that were obtained are in good agreement with the values obtained previously.

  3. An intercomparison between gross α counting and gross β counting for grab-sampling determination of airborne radon progeny and thoron progeny

    NASA Astrophysics Data System (ADS)

    Papp, Z.

    2006-03-01

    The instantaneous values of the airborne activity concentrations of radon progeny and thoron progeny have been determined 34 times in a closed and windowless room in a cellar using two independent grab-sampling methods in order to compare the performance of the methods. The activity concentration of radon ( 222Rn) was also measured and it varied between 200 and 650 Bq m -3. Two samples of radon and thoron progeny were collected simultaneously from roughly the same air volume by filtering. For the first method, the isotopes were collected on membrane filter and gross α counting was applied over several successive time intervals. This method was a slightly improved version of the methods that are applied generally for this reason for decades. For the second method, the isotopes were collected on glass-fibre filter and gross β counts were registered over several time intervals. This other method was developed a few years ago and the above series of measurements was the first opportunity to make an intercomparison between it and another similar method based on α counting. Individual radon progeny and thoron progeny activity concentrations (for the isotopes 218Po, 214Pb, 214Bi and 212Pb) were evaluated by both methods. The detailed investigation of the results showed that the systematic deviation of the methods is small but significant and isotope-dependent. The weighted averages of the β/α activity concentration ratios for 218Po, 214Pb, 214Bi, EEDC 222 (Equilibrium-Equivalent Decay-product Concentration of radon progeny) and 212Pb were 0.99±0.03, 0.90±0.02, 1.03±0.02, 0.96±0.02 and 0.80±0.03, respectively. The source of the systematic deviation is probably the inaccurate knowledge of the counting efficiencies mainly in the case of the α-counting method. A significant random-type difference between the results obtained with the two methods has also been revealed. For example, the β/α ratio for EEDC 222 varied between 0.81±0.01 and 1.22±0.03, where the

  4. Age-dependent inhalation doses to members of the public from indoor short-lived radon progeny.

    PubMed

    Brudecki, K; Li, W B; Meisenberg, O; Tschiersch, J; Hoeschen, C; Oeh, U

    2014-08-01

    The main contribution of radiation dose to the human lungs from natural exposure originates from short-lived radon progeny. In the present work, the inhalation doses from indoor short-lived radon progeny, i.e., (218)Po, (214)Pb, (214)Bi, and (214)Po, to different age groups of members of the public were calculated. In the calculations, the age-dependent systemic biokinetic models of polonium, bismuth, and lead published by the International Commission on Radiological Protection (ICRP) were adopted. In addition, the ICRP human respiratory tract and gastrointestinal tract models were applied to determine the deposition fractions in different regions of the lungs during inhalation and exhalation, and the absorption fractions of radon progeny in the alimentary tract. Based on the calculated contribution of each progeny to equivalent dose and effective dose, the dose conversion factor was estimated, taking into account the unattached fraction of aerosols, attached aerosols in the nucleation, accumulation and coarse modes, and the potential alpha energy concentration fraction in indoor air. It turned out that for each progeny, the equivalent doses to extrathoracic airways and the lungs are greater than those to other organs. The contribution of (214)Po to effective dose is much smaller compared to that of the other short-lived radon progeny and can thus be neglected in the dose assessment. In fact, 90 % of the effective dose from short-lived radon progeny arises from (214)Pb and (214)Bi, while the rest is from (218)Po. The dose conversion factors obtained in the present study are 17 and 18 mSv per working level month (WLM) for adult female and male, respectively. This compares to values ranging from 6 to 20 mSv WLM(-1) calculated by other investigators. The dose coefficients of each radon progeny calculated in the present study can be used to estimate the radiation doses for the population, especially for small children and women, in specific regions of the world

  5. Radon progeny size distributions and enhanced deposition effects from high radon concentrations in an enclosed chamber.

    PubMed

    Leonard, Bobby E

    2004-01-01

    Prior work studying radon progeny in a small enclosed chamber found that at high (222)Rn concentrations an enhanced surface deposition was observed. Subsequent measurements for unfiltered air showed minimal charged particle mobility influence. Progeny particle size measurements reported here, performed at the US Department of Energy Environmental Measurement Laboratory (now with Home Security Department), using the EML graded screen array (GSA) system show in unfiltered air that the high (222)Rn levels causes a reduction in the attached (218)Po progeny airborne particulates and formation of additional normal sized unattached ( approximately 0.80 nm) and also even smaller (218)Po below 0.50 nm. At a (222)Rn level of 51 kBq m(-3), 73% of all (218)Po are of a mean particle diameter of about 0.40 +/- 0.02 nm. At this (222)Rn level, the ratio of (218)Po to (222)Rn airborne concentrations is reduced significantly from the concentration ratio at low (222)Rn levels. Similar reductions and size reformations were observed for the (214)Pb and (214)Bi/Po progeny. The particle size changes are further confirmed using the plateout rates and corresponding deposition velocities. The Crump and Seinfeld deposition theory provides the corresponding particle diffusion coefficients. With the diffusion coefficient to ultrafine clustered particle diameter correlation of Ramamurthi and Hopke, good agreement is obtained between EML GSA and deposition velocity data down to 0.40 nm. Strong evidence is presented that the progeny size reduction is due to, as a result of air ionization, the increased neutralization rate (primarily from electron scavenging of OH molecules) of the initially charged progeny. This is shown to increase with the (1/2) power of (222)Rn concentration and relative humidity as well as increased air change rate in the chamber. These results imply that at (222)Rn levels above 50 kBq m(-3), at relative humidity of 52%, a considerable reduction in lung dose could occur from

  6. Integrated measurements of short-lived 222Rn progeny by rotating filters.

    PubMed

    Pressyanov, D S; Guelev, M G; Pentchev, O J

    1993-05-01

    The dependence of the risk from inhalation of radon progeny on their disequilibrium suggests that the measurements of the time-integrated concentrations of each of the short-lived radon progeny are necessary for complete risk estimations. This paper presents a method that, in principle, allows the determination of the integrated specific volume activities in air of each of the radionuclides 218Po, 214Pb, 214Bi, 212Pb, and 212Bi. The method employs thermoluminescence detectors positioned around uniformly rotating filters. Two prototypes that are suitable for practical applications are described and mathematical expressions for data processing are given. Experiments with these "rotating filter dosimeters" were conducted in atmospheres radiologically dominated by 222Rn progeny. The comparison between the results obtained by the proposed method and those given by simultaneously conducted series of instantaneous grab-sampling measurements support the conclusion that the method works for 222Rn progeny. The method can be experimentally extended for 220Rn progeny as well as for unattached fractions. PMID:8387983

  7. Instrument for measuring total alpha particle energies of alpha emitters in ambient air

    NASA Astrophysics Data System (ADS)

    Kronenberg, S.; Brucker, G. J.; Cummings, B.; Bechtel, E.; Gentner, F.; Horne, S.

    2000-11-01

    This paper describes the design, fabrication, testing and evaluation of a self-reading, carbon fiber, electrometer-type instrument. It is used for measuring the total energy of alpha particles emitted in air by progenies of 222Rn ( 218Po, 214Pb, and 214Bi), and sometimes by other types of alpha emitters (e.g. 212Pb, 238U, and 239Pu). The purpose of these measurements is to assess the energy delivered by alpha emission from these sources to the lung tissue. A sample (charged progenies attached to aerosols) is collected on filter paper from a known volume of air and placed on the instrument. The discharge rate indicates the alpha energy in MeV l -1 of air per min that is produced by the alpha emitters. The calibration procedure shows that the instrument has an energy sensitivity for alpha particles of 800.5 MeV/scale unit. The range of the readout scale is 30 units. Measurements of alpha contamination in air were made using this instrument in buildings, private homes and in a standard chamber. The value of the radon concentration in this chamber is traceable back to the US Environmental Protection Agency (EPA) and to the National Institute of Standards and Technology (NIST).

  8. Disequilibrium of radon and its short-lived daughters near the ground with atmospheric stability

    SciTech Connect

    Duenas, C.; Perez, M.; Fernandez, M.C.; Carretero, J.

    1994-06-01

    We have studied the possibility of using the nonequilibrium of radon daughters as an atmospheric tracer. Over a 7-month period, two daily measurements were taken, one in the early morning and another in the early afternoon at a sampling point with a continental climate. The Rn in the atmospheric air is determined by electroprecipitation of Ra A ((218)Po) ions, and the Ra B ((214)Pb) and Ra C ((214)Bi) daughter concentrations are evaluated by gamma spectrometry. The results show a great variation of the activity ratios Ra B/Rn and Ra C/Rn during the sampling period, depending on the time of measurements and weather conditions. The relations between the activity ratios Ra B/Rn and Ra B/Rn with the stability of the atmosphere has been studied. The stability of the atmosphere was established by two methods: Pasquill`s and Turner`s stability categories. In the second case, the relationship between the activity ratios Ra B/Rn and Ra C/Rn with stability was higher.

  9. United role of radon decay products and nano-aerosols in radon dosimetry

    NASA Astrophysics Data System (ADS)

    Smerajec, M.; Vaupotič, J.

    2012-04-01

    The major part of human exposure to natural radiation originates from inhalation of radon (Rn) and radon short-lived decay products (RnDP: 218Po, 214Pb, 214Bi and 214Po). RnDP are formed as a result of α-transformation of radon. In the beginning they are positive ions which neutralize and form clusters with air molecules, and later partly attach to background aerosol particles in indoor air. Eventually, they appear as radioactive nano-aerosols with a bimodal size distribution in ranges of 1-10 nm (unattached RnDP) and of 200-800 nm (attached RnDP). When inhaled, they are deposited in the respiratory tract. Deposition is more efficient for smaller particles. Therefore, the fraction (fun) of the unattached RnDP, which appears to be influenced by the number concentration and size distribution of general (background) aerosols in the ambient air, has a crucial role in radon dosimetry. Radon, radon decay products and general aerosols have been monitored simultaneously in the kitchen of a typical rural house under real living conditions, also comprising four human activities generating particular matter: cooking and baking, as two typical activities in kitchen, and cigarette smoking and candle burning. In periods without any human activity, the total number concentration of general aerosol ranged from 1000 to 3000 cm-3,with the geometric mean of particle diameter in the range of 60-68 nm and with 0.1-1 % of particles smaller than 10 nm. Preparation of coffee changed the concentration to 193,000 cm-3, the geometric mean of diameter to 20 nm and fraction of particles smaller than 10 nm to 11 %. The respective changes were for baking cake: 503,000 cm-3, 17 nm and 19 %, for smoking:423,000 cm-3, 83 nm and 0.4 %, and forcandle burning: 945,000 cm-3, 8 nm and 85 %. While, as expected, a reduction of fun was observed during cooking, baking and smoking, when larger particles were emitted, fun did not increase during candle burning with mostly particles smaller than 10 nm

  10. Natural radioactivity in tap waters of Eastern Black Sea region of Turkey.

    PubMed

    Cevik, U; Damla, N; Karahan, G; Celebi, N; Kobya, A I

    2006-01-01

    In this study, the activity concentrations of some radionuclides in tap water samples of the Eastern Black Sea region of Turkey were measured. The activity concentrations of radionuclides (214)Pb, (214)Bi, (40)K, (226)Ra and (137)Cs were determined using high resolution gamma ray spectrometry. Furthermore, (222)Rn activity concentrations in tap water samples were measured using Liquid Scintillation Counting. The mean specific activities of (214)Pb, (214)Bi, (226)Ra, (40)K, (137)Cs and (222)Rn in tap water samples were 6.73, 6, 19.16, 168.57, 5.45 mBq l(-1) and 10.82 Bq l(-1), respectively. These values are comparable with concentrations reported for other countries. The effective doses were determined due to intake of these radionuclides as a consequence of direct consumption of tap water samples. The estimated effective doses were 6.878 x 10(-4) microSv y(-1) for (214)Pb, 4.800 x 10(-4) microSv y(-1) for (214)Bi, 3.916 microSv y(-1) for (226)Ra, 0.763 microSv y(-1) for (40)K, 0.052 microSv y(-1) for (137)Cs and 5.848 microSv y(-1) for (222)Rn. PMID:16030056

  11. Daily variation of radon gas and its short-lived progeny concentration near ground level and estimation of aerosol residence time

    NASA Astrophysics Data System (ADS)

    M, Mohery; A, M. Abdallah; A, Ali; S, S. Baz

    2016-05-01

    Atmospheric concentrations of radon (222Rn) gas and its short-lived progenies 218Po, 214Pb, and 214Po were continuously monitored every four hours at the ground level in Jeddah city, Kingdom of Saudi Arabia. The measurements were performed three times every week, starting from November 2014 to October 2015. A method of electrostatic precipitation of positively charged 218Po and 214Po by a positive voltage was applied for determining 222Rn gas concentration. The short-lived 222Rn progeny concentration was determined by using a filter holder connected with the alpha-spectrometric technique. The meteorological parameters (relative air humidity, air temperature, and wind speed) were determined during the measurements of 222Rn and its progeny concentrations. 222Rn gas as well as its short-lived progeny concentration display a daily and seasonal variation with high values in the night and early morning hours as compared to low values at noon and in the afternoon. The observed monthly atmospheric concentrations showed a seasonal trend with the highest values in the autumn/winter season and the lowest values in the spring/summer season. Moreover, and in parallel with alpha-spectrometric measurements, a single filter-holder was used to collect air samples. The deposited activities of 214Pb and the long-lived 222Rn daughter 210Pb on the filter were measured with the gamma spectrometric technique. The measured activity concentrations of 214Pb by both techniques were found to be relatively equal largely. The highest mean seasonally activity concentrations of 210Pb were observed in the autumn/winter season while the lowest mean were observed in the spring/summer season. The mean residence time (MRT) of aerosol particles in the atmospheric air could be estimated from the activity ratios of 210Pb/214Pb. Project supported by the Deanship of Scientific Research (DSR), King Abdulaziz University, Jeddah (Grant No. 291/965/1434).

  12. Study of natural radioactivity and the state of radioactive disequilibrium in U-series for rock samples, North Eastern Desert, Egypt.

    PubMed

    El-Dine, Nadia Walley

    2008-01-01

    Twenty rock samples collected from North Eastern Desert in Egypt have been investigated. Natural radionuclide contents have been measured by gamma-ray spectrometry employing a shielded HPGe detector. The activities of (238)U, (232)Th and (40)K have been determined in Bq/kg dry weight. The absorbed dose rate of gamma radiation ranged from 100.48 to 22,140.53 nGy/h. The representative external hazard index values (H(ex)) for the corresponding samples were estimated. In the present work, the state of radioactive disequilibrium in the U-series at Wadi Baligh area was studied. The activity ratios between (226)Ra/(214)Pb and (214)Pb/(214)Bi were measured. The thorium-to-uranium concentration ratios (Clark value) were also estimated. PMID:17869529

  13. Experimental setup for radon exposure and first diffusion studies using gamma spectroscopy

    NASA Astrophysics Data System (ADS)

    Maier, Andreas; van Beek, Patrick; Hellmund, Johannes; Durante, Marco; Schardt, Dieter; Kraft, Gerhard; Fournier, Claudia

    2015-11-01

    In order to measure the uptake and diffusion of 222Rn in biological material, an exposure chamber was constructed where cell cultures, biological tissues and mice can be exposed to 222Rn-activities similar to therapy conditions. After exposure, the material is transferred to a gamma spectrometer and the decay of 214Pb and 214Bi is analyzed. From the time kinetics of these decays the total amount of the initial 222Rn concentration can be calculated. In this paper the design and construction as well as first test measurements are reported.

  14. Aerodynamic size associations of natural radioactivity with ambient aerosols

    SciTech Connect

    Bondietti, E.A.; Papastefanou, C.; Rangarajan, C.

    1986-04-01

    The aerodynamic size of /sup 214/Pb, /sup 212/Pb, /sup 210/Pb, /sup 7/Be, /sup 32/P, /sup 35/S (as SO/sub 4//sup 2 -/), and stable SO/sub 4//sup 2 -/ was measured using cascade impactors. The activity distribution of /sup 212/Pb and /sup 214/Pb, measured by alpha spectroscopy, was largely associated with aerosols smaller than 0.52 ..mu..m. Based on 46 measurements, the activity median aerodynamic diameter of /sup 212/Pb averaged 0.13 ..mu..m (sigma/sub g/ = 2.97), while /sup 214/Pb averaged 0.16 ..mu..m (sigma/sub g/ = 2.86). The larger median size of /sup 214/Pb was attributed to ..cap alpha..-recoil depletion of smaller aerosols following decay of aerosol-associated /sup 218/Po. Subsequent /sup 214/Pb condensation on all aerosols effectively enriches larger aerosols. /sup 212/Pb does not undergo this recoil-driven redistribution. Low-pressure impactor measurements indicated that the mass median aerodynamic diameter of SO/sub 4//sup 2 -/ was about three times larger than the activity median diameter /sup 212/Pb, reflecting differences in atmospheric residence times as well as the differences in surface area and volume distributions of the atmospheric aerosol. Cosmogenic radionuclides, especially /sup 7/Be, were associated with smaller aerosols than SO/sub 4//sup 2 -/ regardless of season, while /sup 210/Pb distributions in summer measurements were similar to sulfate but smaller in winter measurements. Even considering recoil following /sup 214/Po ..cap alpha..-decay, the avervage /sup 210/Pb labeled aerosol grows by about a factor of two during its atmospheric lifetime. The presence of 5 to 10% of the /sup 7/Be on aerosols greater than 1 ..mu..m was indicative of post-condensation growth, probably either in the upper atmosphere or after mixing into the boundary layer.

  15. Natural radionuclide accumulation by raindrops

    NASA Astrophysics Data System (ADS)

    Gusev, Anatoly; Martin, Inacio; Shkevov, Rumen; Alves, Mauro

    2016-07-01

    The laboratory of environmental radiation of ITA (São José dos Campos, 23°11'11″S, 45°52'43″W, 650 MAMSL) performs simultaneous monitoring of a natural radiation background and meteorological parameters. A time resolution of up to 1 minute allows a detailed comparison of changes in meteorological parameters with those of a concentration of ambient radon progenies in the atmosphere. Results of a study of variation of a fallout of radon progenies ^{214}Pb and ^{214}Bi concomitanting rainfalls are present. The radionuclide fallout rate is reconstructed from the observed gamma rate through a simulation of the first kind Volterra integral equation with difference kernel, determined by ratio of precipitating rates of 214Pb and 214Bi and their decay half times. An original straightforward step-by-step procedure was used for the numerical solution of the equation. The radionuclide concentration in the rainwater is calculated as a ratio of the reconstructed fallout to the measured rainfall. It was observed that the radionuclide fallout rate increases as the rainfall one in approximately power 0.6, i.e. the same as the mean raindrop volume. The concentration thereafter decreases as the rainfall rate in power 0.4. A numerical simulation of the process of accumulation of the radionuclides during diffusion and coalescence drop growth and aerosol scavenging during a passage from a cloud to the ground was performed. The results of the simulations agree with the experimental data.

  16. Natural and anthropogenic radionuclides in airborne particulate samples collected in Barcelona (Spain).

    PubMed

    Vallés, I; Camacho, A; Ortega, X; Serrano, I; Blázquez, S; Pérez, S

    2009-02-01

    Results for naturally occurring (7)Be, (210)Pb, (40)K, (214)Bi, (214)Pb, (212)Pb, (228)Ac and (208)Tl and anthropogenic (137)Cs in airborne particulate matter in the Barcelona area during the period from January 2001 to December 2005 are presented and discussed. The (212)Pb and (208)Tl, (214)Bi and (214)Pb, (7)Be and (210)Pb radionuclide levels showed a significant correlation with each other, with correlation coefficients of 0.99, 0.78 and 0.69, respectively, suggesting similar origin/behaviour of these radionuclides in the air. Caessium-137 and Potassium-40 were transported to the air as resuspended particle from the soil. The (7)Be and (210)Pb concentrations showed similar seasonal variations, with a tendency for maximum concentrations during the summer months. An inverse relationship was observed between the (7)Be, (210)Pb, (40)K and (137)Cs concentrations and weekly rainfall, indicating washout of atmospheric aerosols carrying these radionuclides. PMID:19027201

  17. Radiometric Meteorology: radon progeny as tracers

    NASA Astrophysics Data System (ADS)

    Greenfield, Mark; Iwata, Atsushi; Ito, Nahoko; Kubo, Kenya; Komura, Kazu; Ishizaki, Miho

    2008-10-01

    In-situ measurement of atmospheric γ radiation from radon progeny determine rain and snow rates to better accuracy than standard rain gauges and gives a handle on how droplets are formed. The measured γ ray rates (GRR) have been shown to be proportional to a power of radiometric precipitation rates (RPR)^α, α giving a handle on the extent to which radon progeny are surface adsorbed or volume absorbed.ootnotetextM. B. Greenfield et al., J. Appl. Phys. 93, (2003) pp 5733-5741. More recently time dependent ratios of GRR from ^214Pb and ^214Bi, concentrated from collected rainwater, have been used to determine the elapsed time since activity from RPR, adhered to rain droplets, was removed from secular equilibrium. Ion exchange resins precipitate out the ^214Pb and ^214Bi ions, which are then filtered from 10s of liters of rainwater or snowmelt. A portable Ge detector is used to integrate the resulting activity over 5-10 min intervals. The measured evolution of these two activities from secular equilibrium to transient equilibrium has meteorological applications enabling both the determination of average elapsed times between the formation of raindrops and the time they reach the ground, as well as an estimate of the initial activity at the source of droplet formation.

  18. Measurement of radioactivity levels and assessment of radioactivity hazards of soil samples in Karaman, Turkey.

    PubMed

    Agar, O; Boztosun, I; Korkmaz, M E; Özmen, S F

    2014-12-01

    In this study, the levels of the natural and artificial radioactivity in soil samples collected from surrounding of Karaman in Turkey were measured. Activity concentrations of the concerned radionuclides were determined by gamma-ray spectrometry using a high-purity germanium detector with a relative efficiency of 40 % at 1.332 MeV. The results obtained for the (238)U series ((226)Ra, (214)Pb and (214)Bi), (232)Th series ((228)Ac), (40)K and fission product (137)Cs are discussed. To evaluate the radiological hazard of radioactivity in samples, the radium equivalent activity (Raeq), the absorbed dose rate (D), the annual effective dose and the external (Hex) and internal hazard index (Hin) were calculated and presented in comparison with the data collected from different areas in the world and Turkey. PMID:24587487

  19. Radionuclides in hot mineral spring waters in Jordan.

    PubMed

    Saqan, S A; Kullab, M K; Ismail, A M

    2001-01-01

    Hot mineral springs in Jordan are very attractive to people who seek physical healing but they are unaware of natural radioactive elements that may be contained in the hot mineral water. The activities of the natural radioactive isotopes were measured and the concentrations of the parents of their natural radioactive series were calculated. The measured radionuclides were 234Th, 226Ra, 214Pb, 214Bi, 228Ac, 228Th, 212Pb, 212Bi and 208Tl. In addition the activities of 235U and 40K were measured. The activities ranged from 0.14 to 34.8 Bq/l, while the concentrations of parent uranium and thorium isotopes ranged from 3.0 x 10(-3) to 0.59 mg/l. The results were compared with those for drinking water. PMID:11202689

  20. Conversion factors for external gamma dose derived from natural radionuclides in soils.

    PubMed

    Quindos, L S; Fernández, P L; Ródenas, C; Gómez-Arozamena, J; Arteche, J

    2004-01-01

    Field in situ gamma radiation exposure rates and laboratory measured radioactivity contents of 1500 Spanish soils were compared. The main objective was to determine if published theoretically derived conversion factors would yield accurate quantitative activity concentration (Bq kg(-1)) for the data carried out in different surveys developed by our laboratory during the last ten years. The in situ external gamma dose rate results were compared to laboratory gamma analysis of soils samples gathered from each site, considering the concentrations of seven radionuclides: 40K, 214Pb, 214Bi, 212Bi, 212Pb, 208Tl and 228Ac. The coefficient of correlation found between these variables indicate a good relationship. A discussion of the factors contributing to the uncertainties as well as measurement procedure are also given in this paper. PMID:14567949

  1. A portable battery-powered continuous airborne {sup 222}Rn sampler

    SciTech Connect

    Scarpitta, S.; Kadnar, M.

    1998-04-01

    The Polyport, designed at the Environmental Measurements Laboratory (EML) for deployment in atmospheric balloons or remote areas, was laboratory and field tested to determine its effectiveness in collecting {sup 222}Rn gas in dry and humid air. Twelve 6-cm long tubes containing 0.4 g of Carboxen{trademark}-564 a hydrophobic beaded carbon molecular sieve (BCMS) material efficiently adsorbs airborne {sup 222}Rn under dynamic sampling conditions of 1--2 hr duration. The exposed sorbent is later weighed for water uptake, transferred and counted in a low background liquid scintillation (LS) counter that can detect alpha and beta emitting {sup 222}Rn progeny with a maximum counting efficiency of 5 cpm per dpm. Each sorbent tube can be gamma counted if it contains sufficient adsorbed {sup 214}Pb and {sup 214}Bi activity. The variables tested were sampling flow rate, temperature, sampling time and relative humidity (RH).

  2. An autonomous in situ detection system for radioactivity measurements in the marine environment.

    PubMed

    Tsabaris, C; Bagatelas, C; Dakladas, Th; Papadopoulos, C T; Vlastou, R; Chronis, G T

    2008-10-01

    A new detection system named "KATERINA" is developed and applied for measuring marine radioactivity using NaI(Tl) as a crystal. This apparatus is designed for qualitative and quantitative radionuclide detection in the marine environment with maximum depth of deployment 400 m. A detailed study for the enclosure of the system and for the electronics development is performed. The system offers volumetric activities in Bq/m(3) using the marine efficiency calibration, which is measured by dilution of three reference sources ((99m)Tc, (137)Cs, and (40)K) in a special tank. The calibration procedures for energy, energy resolution and efficiency were analyzed with particular attention to the factors that affect the calibration parameters. The underwater detector is tested in the field for acquiring radon daughters ((214)Pb and (214)Bi) in a region where submarine groundwater discharge exists in the coastal zone. PMID:18372182

  3. Characterization of uranium bearing material using x-ray fluorescence and direct gamma-rays measurement techniques

    NASA Astrophysics Data System (ADS)

    Mujaini, M.; Chankow, N.; Yusoff, M. Z.; Hamid, N. A.

    2016-01-01

    Uranium ore can be easily detected due to various gamma-ray energies emitted from uranium daughters particularly from 238U daughters such as 214Bi, 214Pb and 226Ra. After uranium is extracted from uranium ore, only low energy gamma-rays emitted from 235U may be detected if the detector is placed in close contact to the specimen. In this research, identification and characterization of uranium bearing materials is experimentally investigated using direct measurement of gamma-rays from 235U in combination with the x-ray fluorescence (XRF) technique. Measurement of gamma-rays can be conducted by using high purity germanium (HPGe) detector or cadmium telluride (CdTe) detector while a 57Coradioisotope-excited XRF spectrometer using CdTe detector is used for elemental analysis. The proposed technique was tested with various uranium bearing specimens containing natural, depleted and enriched uranium in both metallic and powder forms.

  4. GAMMA-RAY CHARACTERIZATION OF THE U-SERIES INTERMEDIATE DAUGHTERS FROM SOIL SAMPLES AT THE PENA BLANCA NATURAL ANALOG, CHIHUAHUA, MEXICO

    SciTech Connect

    D.C. French; E.Y. Anthony; P.C. Goodell

    2005-07-18

    The Pena Blanca natural analog is located in the Sierra Pena Blanca, approximately 50 miles north of Chihuahua City, Mexico. The Sierra Pena Blanca is composed mainly of ash-flow tuffs, and the uranium in the region is contained in the brecciated zones of these tuffs. The Pena Blanca site is considered a natural analog to the proposed Yucca Mountain Nuclear Waste Repository because they share similar characteristics of structure, volcanic lithology, tectonic activity, and hydrologic regime. One of the mineralized zones, the Nopal I deposit, was mined in the early 1980s and the ore was stockpiled close to the mine. This stockpile area has subsequently been cleared and is referred to as the prior high-grade stockpile (PHGS) site. Soil surrounding boulders of high-grade ore associated with the PHGS site have been sampled. The purpose of this study is to characterize the transport of uranium series radioisotopes from the boulder to the soil during the past 25 years. Transport is characterized by determining the activities of individual radionuclides and daughter to parent ratios. The daughter to parent ratios are used to establish whether the samples are in secular equilibrium. Activities are determined using gamma-ray spectroscopy. Isotopes of the uranium series decay chain detected by gamma-ray spectroscopy include {sup 210}Pb, {sup 234}U, {sup 234}Th, {sup 230}Th, {sup 226}Ra, {sup 214}Pb, {sup 214}Bi, and {sup 234}Pa. Preliminary results indicate that some daughter to parent pairs appear to be in secular disequilibrium. Thorium is in excess relative to uranium, and radium is in excess relative to thorium. A deficiency appears to exist for {sup 210}Pb relative to {sup 214}Bi and {sup 214}Pb. If these results are borne out by further analysis, they would suggest transport of nuclides from the high-grade boulder into its surroundings, followed by continued leaching of uranium and lead from the environment.

  5. Comparison of in situ and laboratory gamma spectroscopy of natural radionuclides in desert soil.

    PubMed

    Benke, R R; Kearfott, K J

    1997-08-01

    In situ and laboratory gamma spectroscopy were used to characterize natural background levels of radiation in the soil at eight sites around the Yucca Mountain Range. The purpose of this practical field analysis was to determine if published empirical in situ calibration factors would yield accurate quantitative specific activities (Bq kg(-1)) in a desert environment. Corrections were made to the in situ calibration factors to account for the on-axis response of a detector with a thin beryllium end window. The in situ gamma spectroscopy results were compared to laboratory gamma spectroscopy of soil samples gathered from each site. Five natural radionuclides were considered: 40K, 214Pb, 214Bi, 208Tl, and 228Ac. The in situ determined specific activities were consistently within +/-15% of the laboratory soil sample results. A quantitative discussion of the factors contributing to the uncertainty in the in situ and laboratory results is included. Analysis on the specific activity data using statistical hypothesis tests determined that three nuclides, 214Pb, 214Bi, and 228Ac showed a weak site dependence while the other two nuclides, 40K and 208Tl, did not exhibit a site dependence. Differing radiation background levels from site to site along with in situ and laboratory uncertainties in excess of 10% are two factors that account for the weak site dependence. Despite the good correlation between data, it was recommended that the in situ detector be calibrated by a detector-specific Monte Carlo code which would accurately model more complex geometries and source distributions. PMID:9228170

  6. Determination of rain age via {gamma} rays from accreted radon progeny

    SciTech Connect

    Greenfield, M. B.; Ito, N.; Iwata, A.; Kubo, K.; Ishigaki, M.; Komura, K.

    2008-10-01

    The relative {gamma} ray activities from {sup 214}Pb and {sup 214}Bi condensed from precipitation are used to determine its 'age', the average time the accreted activity has been removed from secular equilibrium. A verifiable assumption that radon progeny on/in the surface/volume of droplets mostly remains in secular equilibrium until they begin their descent, enables estimates of their transit times to ground of typically a few tens of minutes. This agrees well with the time expected for the activity on the surface of droplets to reach the ground from heights of a few kilometers. The half lives of {gamma} activities from {sup 214}Bi and {sup 214}Pb, 19.7 and 26.9 min, respectively, are on the same scale as transit time to ground and close enough to each other to measure ratios of activities from secular equilibrium (1.00) to transient equilibrium (3.88) within a few hundreds of minutes. The ratio of {gamma} count rates is independent of knowledge of either initial activity or any systematic errors and thus limited only by the uncertainty from counting statistics, which from condensates of 5-30 l of rain viewed with 2{pi} solid angle by a 50% efficient, high-resolution Ge detector is only a few percent. These ratios fit extremely well to known theoretical curves, which cannot only be used to date rain but can also be extrapolated backward to determine radon progeny activities in rain prior to its descent, knowledge of which may facilitate further studies using radon progeny as tracers.

  7. On-line continuous monitoring of groundwater radon levels at L’Aquila fault, Italy

    NASA Astrophysics Data System (ADS)

    Tsabaris, C.; Lampousis, A.

    2009-12-01

    This work describes in situ radon progeny measurements in the Gran Sasso National Laboratory (LNGS) of L’Aquila region, located 60 miles north-east of Rome, Italy, conducted in December 2007. The marine radon progeny monitor KATERINA (i.e., Hellenic Centre for Marine Research patent July 2008) was submerged inside a tank filled with groundwater from the Gran Sasso Mountain. The measured spectra obtained through KATERINA exhibited photopeaks of the main gamma emitters (214Pb and 214Bi) of the primordial nucleus 238U (222Rn). High background levels of radionuclides (i.e., inside the mountain) emitting high energy gamma rays affected the measurement. In order to correct and deduce the final volumetric activities of radon progenies (214Pb and 214Bi) the system was calibrated using the simulation tool GEANT4. The first day of deployment an averaged value of radon progenies amounted to a value of (3.1 ± 0.3) Bq/l. The second day the averaged values of radon progenies were reduced by 30% due to the loss of noble gas radon from the tank. Additional spectra were recorded successfully after removing background airborne radon present in the LNGS laboratory. KATERINA operated reliably during its in situ radon monitoring. This was confirmed by further calibration using off line measurements performed in collaboration with the Marine Environmental Laboratory of the International Atomic Energy Agency (IAEA). Future work includes the development of a continuous radon monitoring tool to further study the L’Aquila fault. By implementing a continuous inflow and outflow system and by controlling the radon levels both inside and outside the water tank, radon variations will be correlated with other geophysical/geochemical parameters like microseismicity, slip rates, pH, H2S, CO2, and He. Additional contributions include an increased understanding of the correlations between radon levels in the proximity of active faults and regional seismic activity. If indeed this proves to be an

  8. Differences between the activity size distributions of the different natural radionuclide aerosols in outdoor air

    NASA Astrophysics Data System (ADS)

    Gründel, M.; Porstendörfer, J.

    The results of the activity size distribution of the short-lived ( 218Po, 214Bi/ 214Po) and long-lived ( 210Pb, 210Po) radon decay product aerosols, the thoron decay product aerosols ( 212Pb, 212Po) and 7Be of the outdoor atmosphere are presented. The results were obtained from measurements averaged over an extended period (4 weeks) and were carried out with a low-pressure On-Line Alpha Cascade Impactor (OLACI). The size distributions of the radionuclides were obtained from the same measurement run with the OLACI, so that the size classification technique and the atmospheric and weather conditions for all radionuclides were identical. This measurement technique made it possible to measure the correct differences between the size distributions of the different natural radionuclides in the environmental air. The differences between the activity size distributions of the long- and short-lived radionuclides could be explained by coagulation with aerosol particles of the atmosphere as for instance 210Pb was shown.

  9. Study on radon and radon progeny in some living rooms.

    PubMed

    Mohamed, A

    2005-01-01

    In the first part of this work, the potential alpha energy concentration (PAEC) of radon progeny, the equilibrium factor (F), the activity concentration of 222Rn gas (Co) and the unattached fraction (fp), were determined in 15 living rooms at El-Minia City, Egypt. The activity size distribution of (214)Pb was measured by using a low pressure Berner impactor. Based on the parameters of that distribution the total effective dose through the human lung was evaluated by using a dosimetric model calculation of ICRP. An electrostatic precipitation method was used for the determination of 222Rn gas concentration. The mean activity concentration of 222Rn gas (Co) was found to be 123 +/- 22 Bq m(-3). A mean unattached fraction (fp) of 0.11 +/- 0.02 was obtained at a mean aerosol particle concentration (Z) of (3.0 +/- 0.21) x 10(3) cm(-3). The mean equilibrium factor (F) was determined to be 0.35 +/- 0.03. The mean PAEC was found to be 37 +/- 8.1 Bq m(-3). The activity size distribution of (214)Pb shows mean activity median diameter of 290 nm with mean geometric standard deviation (sigma) of 2.45. At a total deposition fraction of approximately 23% the total effective dose to the lung was determined to be approximately 1.2 mSv. The second part of this paper deals with a study of natural radionuclide contents of samples collected from the building materials of those rooms under investigation given in part one of this paper. Analyses were performed in Marinelli beakers with a gamma multichannel analyser provided with a NaI(Tl) detector. The samples have revealed the presence of the uranium-radium and thorium radioisotopes as well as (40)K. Nine gamma-lines of the natural radioisotopes that correspond to 212Pb, 214Pb, 214Bi, 228Ac, 40K and 208Tl were detected and measured. The activity concentrations of 226Ra, 232Th and 40K were determined with mean specific activities of 65 +/- 22, 35 +/- 12 and 150 +/- 60 Bq kg(-1), respectively. These activities amount to a radium equivalent

  10. Intercomparison of γ-spectrometry analysis of radionuclides between China and Japan in 2012-2013.

    PubMed

    Zhou, Qiang; Wang, Xiaoqiang; Tuo, Fei; Han, Yanqing; Ikeuchi, Yoshihiro; Yang, Jia; Xu, Cuihua; Zhang, Jing; Li, Wenhong; Zhang, Qing; Su, Xu

    2015-11-01

    An intercomparison of γ-spectrometry measurement and analysis was organized by the Japan Chemical Analysis Center (JCAC), the National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention (NIRP, China CDC), and the Radiation Monitoring Technical Center of Ministry of Environmental Protection, Chinese (RMTC). The main objective of this study was to assess the γ-spectrometry measurement and analysis technology. The JCAC completed the collection and preparation of soil and powdered rice samples. Three laboratories compared the measurement of seven radionuclides that included two samples of (214)Pb, (214)Bi, (208)Tl, (228)Ac, (40)K, (137)Cs, and (134)Cs with γ-spectrometry. During the studies conducted at the laboratory, the calculated value En was found to be the total uncertainty data of the reported activity. Except (134)Cs in powdered rice sample, the calculated En between each of the two laboratories was <1. The measurement results are acceptable except (134)Cs; therefore, measurement results in the three laboratories were consistent within a certain range except in the case of (134)Cs. Although there is a need to improve the accuracy of measurements and analysis of (134)Cs, an intercomparison was conducted of the tested levels on radionuclide analyzed in the three laboratories. PMID:26343339

  11. Natural Radionuclides In Mineral Sand Products From A Processing Plant In Northeastern Brazil

    SciTech Connect

    Hazin, C. A.; Khoury, H. J.; Silveira, S. V.

    2008-08-07

    This paper presents the results of a preliminary investigation carried out in a mineral sand processing plant located in the coastal region of Northeastern Brazil. The study aimed to determine the natural radionuclide content of the mineral products extracted from beach sands, with special emphasis on zircon. Measurements were performed through gamma spectrometry, by using a high-purity germanium detector (HPGe) coupled to a multichannel analyzer. Activity concentrations of {sup 226}Ra and {sup 228}Ra were determined by measuring some of the radon progeny activity concentrations ({sup 214}Pb and {sup 214}Bi for {sup 226}Ra, and {sup 228}Ac and {sup 208}Tl for {sup 228}Ra) and assuming an equilibrium condition upstream of the radon progeny. The results of the measurements carried out for the zircon samples showed activity concentrations ranging from 18.09 to 48.51 kBq kg{sup -1} for {sup 226}Ra. The results for {sup 228}Ra, on the other hand, were consistently lower than those obtained for {sup 226}Ra, ranging from 2.72 to 18.31 kBq kg{sup -1}.

  12. Radionuclide Concentrations in Soils and Vegetation at Low-Level Radioactive Waste Disposal Area G during the 1997 Growing Season

    SciTech Connect

    L. Naranjo, Jr.; P. R. Fresquez; R. J. Wechsler

    1998-08-01

    Soil and overstory and understory vegetation (washed and unwashed) collected at eight locations within and around Area G-a low-level radioactive solid-waste disposal facility at Los Alamos National Laboratory-were analyzed for 3H, 238Pu, 239Pu, 137CS, 234U, 235U, 228AC, Be, 214Bi, 60Co, 40& 54Mn, 22Na, 214Pb and 208Tl. In general, most radionuclide concentrations, with the exception of 3Ef and ~9Pu, in soils and overstory and understory vegetation collected from within and around Area G were within upper (95'%) level background concentrations. Although 3H concentrations in vegetation from most sites were significantly higher than background (>2 pCi mL-l), concentrations decreased markedly in comparison to last year's results. The highest `H concentration in vegetation was detected from a juniper tree that was growing over tritium shaft /+150; it contained 530,000 pCi 3H mL-l. Also, as in the pas~ the transuranic waste pad area contained the highest levels of 239Pu in soils and in understory vegetation as compared to other areas at Area G.

  13. Radionuclide concentrations in soils and vegetation at radioactive-waste disposal Area G during the 1996 growing season. Progress report

    SciTech Connect

    Fresquez, P.R.; Vold, E.L.; Naranjo, L. Jr.

    1997-07-01

    Soil and overstory and understory vegetation (washed and unwashed) collected at eight locations within and around Area G--a low-level radioactive solid-waste disposal facility at Los Alamos National laboratory--were analyzed for {sup 3}H, {sup 90}Sr, {sup 238}Pu, {sup 239}Pu, {sup 137}Cs, {sup 234}U, {sup 235}U, {sup 238}U, {sup tot}U, {sup 228}Ac, {sup 214}Bi, {sup 60}Co, {sup 40}K, {sup 54}Mn, {sup 22}Na, {sup 214}Pb, and {sup 208}Tl. Also, heavy metals (Ag, As, Ba, Be, Cd, Cr, Hg, Ni, Pb, Sb, Se, and Tl) in soil and vegetation were determined. In general, most radionuclide concentrations, with the exception of {sup 3}H and {sup 239}Pu, in soils and washed and unwashed overstory and understory vegetation collected from within and around Area G were within upper limit background concentrations. Tritium was detected as high as 14,744 pCi mL{sup {minus}1} in understory vegetation collected from transuranic (TRU) waste pad {number_sign}4, and the TRU waste pad area contained the highest levels of {sup 239}Pu in soils and in understory vegetation as compared to other areas at Area G.

  14. Measurement of radon decay products and thoron decay products in air by beta counting using end-window Geiger-Muller counter.

    PubMed

    Papp, Z; Daróczy, S

    1997-04-01

    A new grab sampling method has been developed for the simultaneous measurement of radon decay products and thoron decay products in air. It is based on direct beta counting of filtered aerosol sample over successive time intervals by end-window Geiger-Muller counter. Defined solid angle absolute counting was used to evaluate the efficiencies for the decay products one by one. Absolute activity concentrations can be determined with less than 10% systematic error. Glass-fiber filter, high sampling flow rate, and long duration of sampling can be used, as a result of which the detection limits are about 0.1, 0.2, and 0.01 Bq m(-3) for 214Pb, 214Bi, and 212Pb, respectively. Indoor saturated activity concentrations were measured in 86 buildings in Ajka town, Hungary, where industrial wastes rich in uranium had been used as building materials. Elevated radon decay product levels were found in houses built before 1960. Radon gas concentration was also measured simultaneously in 26 cases and the minimum, maximum, and average values of the equilibrium factor were 0.17, 0.73, and 0.40, respectively. PMID:9119685

  15. Analysis of chemical samples for environmental levels of radioactivity using a massively shielded 18% Ge(Li) system

    NASA Astrophysics Data System (ADS)

    Blanchard, Fred A.; Lickly, Tim D.

    1984-01-01

    An environmental level gamma radioactivity analysis system has been assembled from a commercially available, high sensitivity, high resolution, low background Ge(Li) detector with associated electronics (without coincidence or anticoincidence) and massive shielding with old iron. A variety of chemicals have been examined as part of a background baseline survey using quantitative peak or gross gamma analysis of the Ge(Li) gamma ray spectrum from a two liter sample in a Marinelli beaker. Gamma peak analysis had a calculated sensitivity (for a 30 min count) of 0.01 to 0.21 pCi/g, depending on sample bulk density, for an isotope such as 137Cs. A similar sensitivity (0.1 pCi/g) was obtained by gross gamma analysis for any mixture of isotopes. A method for estimating the necessary integral background value for samples of different bulk densities was developed. The methods are capable of demonstrating existing natural radioactivity as shown by the 40K and uranium, thorium and their daughters observed in about 16% of the chemicals tested. Especially noticeable were 40K, 228Ac, 212Pb, 208Tl, 214Pb, and 214Bi. The levels and isotopes were similar to those found in soils and common salts.

  16. IXth millenium B.C. ceramics from Niger: detection of a U-series disequilibrium and TL dating

    NASA Astrophysics Data System (ADS)

    Guibert, P.; Schvoerer, M.; Etcheverry, M. P.; Szepertyski, B.; Ney, C.

    A set of pottery sherds collected from two ancient neolithic sites in Niger (Tagalagal and Adrar Bous 10) has been dated by thermoluminescence. The natural radioactivity of these ceramics and of their surrounding sediments was measured using low background gamma spectrometry and atomic emission plasma spectrometry. With gamma spectrometry, the comparison between the activity of 238U (deduced from the 235U and 234Th gamma emissions) and that of 226Ra (deduced from 214Pb and 214Bi γ emissions in equilibrium with 222Rn) shows a significant disequilibrium of the U-series. The activity ratio {38U}/{226Ra}, which is greater than unity in this case, is interpreted as a result of either uranium enrichment ( 234U, 235U, 238U) or radium impoverishment that has been occurring since the burying of the archaeological artefacts. The effects of the changes in radiochemical composition on the annual dose are discussed and various determinations of the annual dose are analysed according to different hypotheses of disequilibrium (either permanent state or recent occurrence). The TL results: Tagalagal — 9820±780-10, 180±780 years/1993, Adrar Bous 10 — 9530±750-10,500±730 years/1993, are consistent with the radiocarbon dates obtained from charcoals collected at the same locations (the uncalibrated 14C dates belong to the 9100-9370 BP range). These results are of fundamental interest for the chronology of early neolithic cultures.

  17. Rain-Induced Increase in Background Radiation Detected by Radiation Portal Monitors

    SciTech Connect

    Hausladen, Paul; Blessinger, Christopher S; Guzzardo, Tyler; Livesay, Jake

    2012-07-01

    A complete understanding of both the steady state and transient background measured by Radiation Portal Monitors (RPMs) is essential to predictable system performance, as well as maximization of detection sensitivity. To facilitate this understanding, a test bed for the study of natural background in RPMs has been established at the Oak Ridge National Laboratory. This work was performed in support of the Second Line of Defense Program's mission to detect the illicit movement of nuclear material. In the present work, transient increases in gamma ray counting rates in RPMs due to rain are investigated. The increase in background activity associated with rain, which has been well documented in the field of environmental radioactivity, originates from the atmospheric deposition of two radioactive daughters of radon-222, namely lead-214 and bismuth-214 (henceforth {sup 222}Rn, {sup 214}Pb and {sup 214}Bi). In this study, rainfall rates recorded by a co-located weather station are compared with RPM count rates and High Purity Germanium spectra. The data verifies these radionuclides are responsible for the dominant transient natural background fluctuations in RPMs. Effects on system performance and potential mitigation strategies are discussed.

  18. Dating of sediments from four Swiss prealpine lakes with (210)Pb determined by gamma-spectrometry: progress and problems.

    PubMed

    Putyrskaya, V; Klemt, E; Röllin, S; Astner, M; Sahli, H

    2015-07-01

    In this paper the most important problems in dating lake sediments with unsupported (210)Pb are summarized and the progress in gamma-spectrometry of the unsupported (210)Pb is discussed. The main topics of these studies concern sediment samples preparation for gamma-spectrometry, measurement techniques and data analysis, as well as understanding of accumulation and sedimentation processes in lakes. The vertical distributions of artificial ((137)Cs, (241)Am, (239)Pu) and natural radionuclides ((40)K, (210,214)Pb, (214)Bi) as well as stable trace elements (Fe, Mn, Pb) in sediment cores from four Swiss lakes were used as examples for the interpretation, inter-comparison and validation of depth-age relations established by three (210)Pb-based models (CF-CSR, CRS and SIT). The identification of turbidite layers and the influence of the turbidity flows on the accuracy of sediment dating is demonstrated. Time-dependent mass sedimentation rates in lakes Brienz, Thun, Biel and Lucerne are discussed and compared with published data. PMID:25875007

  19. In situ gamma-ray spectrometry in the environment using dose rate spectroscopy

    NASA Astrophysics Data System (ADS)

    Ji, Young-Yong; Kim, Chang-Jong; Chung, Kun Ho; Choi, Hee-Yeoul; Lee, Wanno; Kang, Mun Ja; Park, Sang Tae

    2016-02-01

    In order to expand the application of dose rate spectroscopy to the environment, in situ gamma-ray spectrometry was first conducted at a height of 1 m above the ground to calculate the ambient dose rate and individual dose rate at that height, as well as the radioactivity in the soil layer for the detected gamma nuclides from the dose rate spectroscopy. The reliable results could be obtained by introducing the angular correction factor to correct the G-factor with respect to incident photons distributed in a certain range of angles. The intercomparison results of radioactivity using ISOCS software, an analysis of a sample taken from the soil around a detector, and dose rate spectroscopy had a difference of <20% for 214Pb, 214Bi, 228Ac, 212Bi, 208Tl, and 40K, except for 212Pb with low-energy photons, that is, <300 keV. In addition, the drawback of using dose rate spectroscopy, that is, all gamma rays from a nuclide should be identified to accurately assess the individual dose rate, was overcome by adopting the concept of contribution ratio of the key gamma ray to the individual dose rate of a nuclide, so that it could be accurately calculated by identifying only a key gamma ray from a nuclide.

  20. U-Sries Disequilibra in Soils, Pena Blanca Natural Analog, Chihuahua, Mexico

    SciTech Connect

    D. French; E. Anthony; P. Goodell

    2006-03-16

    The Nopal I uranium deposit located in the Sierra Pena Blanca, Mexico. The deposit was mined in the early 1980s, and ore was stockpiled close by. This stockpile area was cleared and is now referred to as the Prior High Grade Stockpile (PHGS). Some of the high-grade boulders from the site rolled downhill when it was cleared in the 1990s. For this study soil samples were collected from the alluvium surrounding and underlying one of these boulders. A bulk sample of the boulder was also collected. Because the Prior High Grade Stockpile had no ore prior to the 1980s a maximum residence time for the boulder is about 25 years, this also means that the soil was at background as well. The purpose of this study is to characterize the transport of uranium series radionuclides from ore to the soil. Transport is characterized by determining the activities of individual radionuclides and daughter to parent ratios. Isotopes of the uranium series decay chain detected include {sup 210}Pb, {sup 234}U, {sup 230}Th, {sup 226}Ra, {sup 214}Pb, and {sup 214}Bi. Peak areas for each isotope are determined using gamma-ray spectroscopy with a Canberra Ge (Li) detector and GENIE 2000 software. The boulder sample is close to secular equilibrium when compared to the standard BL-5 (Beaver Lodge Uraninite from Canada). Results for the soils, however, indicate that some daughter/parent pairs are in secular disequilibrium. These daughter/parent (D/P) ratios include {sup 230}Th/{sup 234}U, which is greater than unity, {sup 226}Ra/{sup 230}Th, which is also greater than unity, and {sup 210}Pb/{sup 214}Bi, which is less than unity. The gamma-ray spectrum for organic material lacks {sup 230}Th peaks, but contains {sup 234}U and {sup 226}Ra, indicating that plants preferentially incorporate {sup 226}Ra. Our results, combined with previous studies require multistage history of mobilization of the uranium series radionuclides. Earlier studies at the ore zone could limit the time span for mobilization only

  1. Comparison of Activity Determination of Radium 226 in FUSRAP Soil using Various Energy Lines - 12299

    SciTech Connect

    Tucker, Brian; Donakowski, Jough; Hays, David

    2012-07-01

    Gamma spectroscopy is used at the Formerly Utilized Sites Remedial Action Program (FUSRAP) Maywood Superfund Site as the primary radioanalytical tool for quantization of activities of the radionuclides of concern in site soil. When selecting energy lines in gamma spectroscopy, a number of factors are considered including assumptions concerning secondary equilibrium, interferences, and the strength of the lines. The case of the Maywood radionuclide of concern radium-226 (Ra-226) is considered in this paper. At the FUSRAP Maywood Superfund Site, one of the daughters produced from radioactive decay of Ra-226, lead-214 (Pb- 214), is used to quantitate Ra-226. Another Ra-226 daughter, bismuth-214 (Bi-214), also may be used to quantitate Ra-226. In this paper, a comparison of Ra-226 to Pb-214 activities and Ra-226 to Bi-214 activities, obtained using gamma spectrometry for a large number of soil samples, was performed. The Pb-214, Bi-214, and Ra-226 activities were quantitated using the 352 kilo electron volt (keV), 609 keV, and 186 keV lines, respectively. The comparisons were made after correcting the Ra-226 activities by a factor of 0.571 and both ignoring and accounting for the contribution of a U-235 interfering line to the Ra-226 line. For the Pb-214 and Bi-214 activities, a mean in-growth factor was employed. The gamma spectrometer was calibrated for efficiency and energy using a mixed gamma standard and an energy range of 59 keV to 1830 keV. The authors expect other sites with Ra-226 contamination in soil may benefit from the discussions and points in this paper. Proper use of correction factors and comparison of the data from three different gamma-emitting radionuclides revealed agreement with expectations and provided confidence that using such correction factors generates quality data. The results indicate that if contamination is low level and due to NORM, the Ra-226 can be measured directly if corrected to subtract the contribution from U-235. If there is

  2. New Neutron Rich Nuclei Near {sup 208}Pb

    SciTech Connect

    Aeystoe, J.; Andreyev, A.; Evensen, A.-H.; Hoff, P.; Huhta, M.; Huyse, M.; ISOLDE Collaboration; Jokinen, A.; Karny, M.; Kugler, E.; Kurpeta, J.; Lettry, J.; Nieminen, A.; Plochocki, A.; Ramdhane, M.; Ravn, H.; Rykaczewski, K.; Szerypo, J.; VanDuppen, P.; Walter, G.; Woehr, A.

    1998-11-13

    The level properties near the stable doubly-magic nuclei formed the experimental grounds for the theoretical description of nuclear structure. However with a departure from the beta-stability line, the classical well-established shell structure might be modified. In particular, it may even vanish for extremely exotic neutron-rich nuclei near the neutron-drip line. Presently, it is impossible to verify such predictions by a direct experimental studies of these exotic objects. However, one may try to observe and understand the evolution of the nuclear structure while departing in the experiment as far as possible from the stable nuclei. An extension of experimental nuclear structure studies towards the nuclei characterized by high neutron excess is crucial for such verifications as well as for the {tau}-process nucleosynthesis scenario. Heavy neutron-rich nuclei, south-east of doubly-magic {sup 208}Pb, were always very difficult to produce and investigate. The nuclei like {sup 218}Po and {sup 214}Pb or {sup 210}Tl marked the border line of known nuclei from the beginning of the radioactivity era for over ninety years. To illustrate the difficulties, one can refer to the experiments employing the on-line mass separator technique. A spallation of heavy targets like {sup 232}Th and {sup 238}U by high-energy protons was proven as a source of heavy neutron-rich nuclei. The isotopes near and beyond doubly-magic {sup 208}Pb were produced too. However, such studies often suffered from an isobaric contamination of much more strongly produced and efficiently released elements like francium or radon and their decay products. A new experimental technique, based on the pulsed release element selective method recently developed at the PS Booster-ISOLDE at CERN [7,8,9] greatly reduces the contamination of these very short-lived {alpha}-emitters (Z {ge} 84) for the isobaric mass chains A=215 to A=218.

  3. Environmental radiation levels in soil and sediment samples collected from floating water from a land runway resulting from heavy rains in the Jeddah region, KSA

    NASA Astrophysics Data System (ADS)

    Mohery, M.; Baz, Shadiah; Kelany, Adel M.; Abdallah, A. M.

    2014-04-01

    The natural radiation levels in soil and sediment samples collected from floating water from a land runway resulting from heavy rains in the Jeddah region as well as the activity in the population of its surrounding environments were studied. In the regions surrounding Jeddah, the movements of floating water may increase the concentration of radioactivity due to the movement of soil due to heavy rains. In addition, the technological development of industry, agriculture and other sources around the Jeddah region has increased environmental pollution, resulting in noticeable concentrations of radioactivity. The measured activity concentrations of 214Pb, 214Bi, 228Ac, 208Tl, 40K, 226Ra and 228Ra in the studied area suggest that they are within the world average for soils and sediments, except those for water sample no. 4; the concentration in this sample was five times higher than the world average concentration (this water is not consumable). Herein, the radioactivity concentrations that were obtained from the analysis of soil and sediment samples that were collected from the investigated area are discussed. Additionally, the absorbed dose rate (D), radium equivalent activity (Raeq), external hazard index (Hex), annual gonadal dose equivalent (AGDE) and annual effective dose equivalent (AEDE) were evaluated. For the soil and sediment samples, the average radioactivity concentrations were determined for each site and are expressed in Becquerels per kilogram (Bq/kg) of dry weight, while for the measurement of both the 226Ra and 228Ra isotopes in the water samples, the activity concentration is expressed in picoCuries per liter (pCi/l). The obtained results were compared with other measurements from different countries. The movement of floating water around the Jeddah region increases the concentration of radioactivity due to the movement of soils with heavy rains.

  4. Radiometric analysis of farmed fish (sea bass, gilthead bream, and rainbow trout) from Tenerife Island, Spain.

    PubMed

    Jalili, A; López-Pérez, M; Karlsson, L; Hernández, F; Rubio, C; Hernández-Armas, J; Hardisson, A

    2009-09-01

    This study analyzed the content of gamma-emitting radionuclides in fish farmed on the island of Tenerife (Canary Islands, Spain). The fish species included in this study were sea bass, gilthead bream, and rainbow trout. The first two species are produced in offshore enclosures, while the third is produced in a freshwater fish farm. All measurements were performed using two high-purity germanium gamma-ray detectors. The content of gamma-emitting radionuclides in the fodder used to feed the different species of farmed fish studied was also determined. The following nuclides were often detected in the analyzed samples: 137Cs, 40K, 235U, 228Ac, 214Bi, 208Tl, 212Pb, and 214Pb. As a complement to this analysis, 210Po concentrations in two fish samples were determined by alpha spectrometry. The nuclide presenting the highest concentration was, as expected, the naturally occurring 40K, with an average concentration of 0.13 +/- 0.01 Bq/g (wet weight) (Bq/gww) in gilthead bream and sea bass and 0.12 +/- 0.01 Bq/gww in rainbow trout. The 235U concentrations determined in the same fish species were 0.6 +/- 0.5, 0.8 +/- 0.7, and 1.6 +/- 1.0 mBq/gww, respectively. This nuclide is seldom reported in fish samples. The concentrations of 137Cs (the only artificial nuclide determined in this study) in gilthead bream and sea bass were 0.026 +/- 0.006 and 0.044 +/- 0.01 mBq/gww, respectively. In addition to the radiometric analysis, the contribution of the analyzed nuclides to the effective dose from the mean daily intake of the fish was calculated. The calculated contribution, in terms of dose per person, produced by intake of the analyzed fish was 0.8 microSv/year. This value does not represent a significant risk to the local population. PMID:19777898

  5. Level of natural and artificial radioactivity in Algeria.

    PubMed

    Baggoura, B; Noureddine, A; Benkrid, M

    1998-07-01

    A national environmental sampling program was carried out during 1993 to determine natural and artificial radionuclides contents in the (0-15 cm) upper layer of the soil. The main objective was to establish a radioactive reference level in the whole territory, since 131I, 134Cs and 137Cs were detected in most of the analysed samples collected right after the Chernobyl accident (May 1986). Soil samples were analysed by direct counting by gamma-ray spectrometry. In addition, terrestrial gamma-ray dose rates in air have been measured out of doors throughout Algeria. In each of the 48 administrative divisions of the country selected sites were chosen to collect soil samples and measure gamma-ray dose rates. The gamma-emitting radionuclides resulting from the radioactive decay of 238U and 232Th, 40K and 137Cs were detected in most of the analysed samples. Radioactivity concentrations in Bq kg-1 dry mass in soil samples of 226Ra, 214Pb, 214Bi, 212Pb, 228Ac, 40K and 137Cs range between (5-176), (2-107), (3-65), (2-97), (3-144), (36-1405) and (0.3-41) respectively. In addition, six selected soil samples were analysed to determine plutonium isotopes contents. Radioactivity concentrations in Bq kg-1 dry mass of 238Pu and 239 + 240Pu vary between (0.012-0.013) and (0.24-0.61) respectively. The dose rates in air measured over the whole country were found to range between 20 and 133 nGy h-1. Presence of 137Cs has been clearly observed. An approach has been made to determine its origin, considering the global fallout, the Chernobyl accident and the French nuclear bomb tests in the 60s as the main potential sources. It is concluded that Algeria has indeed been affected by the Chernobyl accident. PMID:9570102

  6. Gross alpha, gross beta activities and gamma emitting radionuclides composition of airborne particulate samples in an oceanic island

    NASA Astrophysics Data System (ADS)

    Hernández, F.; Hernández-Armas, J.; Catalán, A.; Fernández-Aldecoa, J. C.; Karlsson, L.

    The radiometric compositions of airborne particulate samples, collected weekly during a 4 years period (1 January 2000 till 31 December 2003) at a site located 310 m a.s.l. in Tenerife (Canary Islands), are analysed in this paper. To do this, measurements of gross alpha, gross beta, 7Be, 210Pb, 228Ac, 226Ra, 212Pb, 214Pb, 208Tl, 214Bi, 235U, 40K, 131I and 137Cs concentrations were carried out in 376 cellulose and polypropylene filters. The time variations of the different radionuclides concentrations have been discussed in relation with various meteorological factors and the mean values have been compared to those published in recent literature for other sites located at the same altitude but different latitudes. The weekly activities of 7Be correlated linearly with the 210Pb activities ( R=0.59). In disagreement with other published studies, the 7Be activities did not correlate ( R=-0.05) with the temperature and maximum values were not found during summer season. The gross beta activities showed correlations with the gross alpha ( R=0.72) and 210Pb activities ( R=0.52), but not with the 7Be ( R=0.16). The anthropogenic radionuclide 131I, emitted from a nearby hospital, was detected slightly above detection limits (1.73×10 -6 Bq m -3) in 88 of the 210 weeks of measurement considered in this work. 137Cs was detected in 31 of those weeks. The 4-year average calculated for 7Be and 210Pb were 3 and 0.3 mBq m -3, respectively. These values are lower than those expected for a site at comparable latitude and altitude. In general, the radionuclides which appeared most frequently in the airborne particulate filters ( 7Be, 210Pb, 212Pb and 40K), did not correlate significantly with any of the meteorological parameters considered: rainfall, temperature, pressure, relative humidity, visibility, wind speed and direction. Therefore, no predictive model could be established with the available data as it has been done for continental sites. The long-range transport of aerosols

  7. Concurrent determination of 224Ra, 226Ra, 228Ra, and unsupported 212Pb in a single analysis for drinking water and wastewater: dissolved and suspended fractions.

    PubMed

    Parsa, Bahman; Obed, Reynaldo N; Nemeth, William K; Suozzo, Gail

    2004-02-01

    A technique has been developed for the measurement of 224Ra, 226Ra, 228Ra, and unsupported 2t2Pb concurrently in a single analysis. The procedure can be applied to both drinking water and wastewater, including the dissolved and suspended fractions of a sample. For drinking water samples, using 3-L aliquots, the radium isotopes are isolated by a fast PbSO4 co-precipitation and then quantified by gamma-ray spectroscopy. The radium isotopes 224Ra, 226Ra, and 228Ra are measured through their gamma-ray-emitting decay products, 212Pb, 214Pb (and/or 214Bi), and 228Ac, respectively. Because of the short half-life of 224Ra (T1/2 = 3.66 d), the precipitate should be counted within 4 d of the sample collection date. In case the measurement of unsupported 212Pb (T1/2 = 10.64 h) is required, the gamma-ray analysis should be initiated as soon as possible, preferably on the same day of collection. The counting is repeated after about 21 d to ensure the 226Ra progeny are in equilibrium with their parent. At this point, the 228Ac equilibration with its 228Ra parent is already established. In the case of samples containing suspended materials, an aliquot of sample is filtered and then the filtrate is treated as described above for drinking water samples. The suspended fraction of sample, collected on the filter, is directly analyzed by gamma-ray spectroscopy with no further chemical separation. Aliquots of de-ionized water spiked with various radium standards were analyzed to check the accuracy and precision of the method. In addition, analysis results of actual samples using this method were compared with the ones performed using U.S. Environmental Protection Agency-approved procedures, and the measured values were in close agreement. This method simplifies the analytical procedures and reduces the labor while achieving the precision, accuracy, and minimum detection concentration requirements of EPA's Regulations. PMID:14744047

  8. Non-destructive determination of 224Ra, 226Ra and 228Ra concentrations in drinking water by gamma spectroscopy.

    PubMed

    Parekh, Pravin; Haines, Douglas; Bari, Abdul; Torres, Miguel

    2003-11-01

    The U.S. Environmental Protection Agency mandates that drinking water showing gross alpha-activity greater than 0.19 Bq L(-1) should be analyzed for radium, a known human carcinogen. The recommended testing methods are intricate and laborious. The method reported in this paper is a direct, non-destructive gamma-spectroscopic method for the determination of 224Ra, 226Ra, and 228Ra, the three radium isotopes of environmental concern in drinking water. Large-volume Marinelli beakers (4.1-L capacity), especially designed for measuring radioactive gases, in conjunction with a low-background, high-efficiency (131%) germanium detector were used in this work. It was first established that radon, the gaseous decay product of radium, and its progeny are quantitatively retained in this Marinelli beaker. The 224Ra, 226Ra, and 228Ra activity concentrations are determined from the equilibrium activities of their progeny: 212Pb, 214Pb (214Bi), and 228Ac; and the gamma-lines used in the analysis are 238.6, 351.9 (and 609.2), and 911.2 keV, respectively. The 224Ra activity is determined from the first 1,000-min measurement performed after expulsion of radon from the sample. The 226Ra activity is determined from the second, 2,400-min measurement, made 3 to 5 d later, and the 228Ra activity is determined from either the first or the second measurement, depending on its concentration level. The method's minimum detectable activities are 0.017 Bq L(-1), 0.020 Bq L(-1), and 0.027 Bq L(-1) for 224Ra, 226Ra, and 228Ra, respectively, when measured under radioactive equilibrium. These limits are well within the National Primary Drinking Water Regulations required limit of 0.037 Bq L(-1) for 226Ra and for 228Ra. The precision and accuracy of the method, evaluated using the U.S. Environmental Protection Agency and the Environmental Resource Associates' quality control samples, were found to be within acceptable limits. PMID:14571995

  9. Comparison between the Spectra of Gamma Radiation for Climate Dry Periods and Rainy in the Southeast of Brazil

    NASA Astrophysics Data System (ADS)

    Gomes, M. P.; Martin, I. M.

    2013-05-01

    Through this work, present themselves the results obtained for the spectra of ionizing radiation (X-rays and gamma) environmental southeast Brazil for the periods of dry and rainy climate, respectively. One of the objectives this work is promoting through analysis of the results a better understand, in the educational area, the physical processes related to the background radiation of the places where measurements were made. In Brazil, there is still little information about the radiation from soil, radon gas atmospheric, cosmic and artificial origin. Measurements of gamma radiation spectra were performed with a scintillator of NaI (Tl) (volume 300 cm3) mounted within an aluminum cell and coupled to a photomultiplier tube, which in turn is coupled through an interface to specify a notebook for storage of data. The measurement of X and gamma rays photons occur of way omnidirectional without distinction as to direction. The data acquisition was performed at fixed intervals of 1 minute continuously for the entire period of dry climate (June to October) and rainy (December 2012 to January 2013). Figures 1 and 2 show the results obtained for both periods, dry and rainy, respectively. Regarding the graph of Figure 1, is evidenced a cycle of 24 hours in the radiation spectrum. In this period without rain the radiation increases always between sunrise sunset until 11 - 12 hours local, due to the increased presence of radon gas (222Rn) which decays after 3.8 days in 214Pb and 214Bi, emitting photons in the range of energy the detector is measuring (0.030 to 3.0 MeV). The graph in Figure 2 shows that during the rainy period, there was a significant increase in radiation intensity, in addition to that already shown in the dry times that for certain time intervals. This increase is due to when occurs precipitation, the amount of radon gas increases because of the phenomenon of washing the lower atmosphere where the gas is suspended and diluted in water droplets. In the rainy

  10. Self Attenuation of Gamma Rays in Titanite, Zircon and Apatite

    NASA Astrophysics Data System (ADS)

    Walsh, C. N.; Baskaran, M.; Brownlee, S. J.; Eakin, M.

    2013-12-01

    Several of the gamma-emitting U-Th series, cosmogenic and anthropogenic radionuclides (210Pb, 234Th, 226Ra, 228Ra, 7Be, 137Cs, etc) have been widely utilized as tracers and chronometers in environmental studies. Precise measurements of these nuclides using gamma-ray spectrometry in environmental matrices require that the proper correction factors for self- and external-absorption be applied. In this study, we examine factors associated with absorption and self attenuation of gamma-rays of 210Pb (46.5 keV), 234Th (63 keV), 226Ra (via 214Pb and 214Bi, 351.9 and 609 keV) and 228Ra (via 228Ac, 338.3 and 911.2 keV) using a well-type germanium gamma-ray detector. Samples of three naturally occurring minerals (titanite, apatite and zircon) were separated into 5 size fractions (<63 μm, 63-125 μm, 125-250 μm, 250-500 μm, and >500 μm) and analyzed for 210Pb, 234Th, 226Ra, and 228Ra. We also analyzed two synthetic silica standards (RGU-1, RGTH-1) that have a relatively uniform grain size of 63 μm. These minerals were chosen based on their varying chemical compositions and densities. Chosen samples are of an age that isotopes of 238U and 232Th are expected to be in secular equilibrium with their daughter products. However, the measured activity ratios between members of the family vary widely. In the case of titanite, the 210Pb/226Ra ratios in 5 size fractions varied between 0.44×0.03 and 0.53×0.03, while in apatite it varied between 0.54×0.03 and 0.67×0.04, without applying any self- and external-absorption correction factors. Using the attenuation coefficients of constituent elements at different energies, we estimate the attenuation coefficient for each of these 4 minerals and determine the self- and external-absorption correction factors. The self- and external-absorption corrected activities agree with the expected activities in these minerals. Our data suggests that variations in the activity levels are dependent on chemical composition, density, and grain

  11. Preliminary study of a radiological survey in an abandoned uranium mining area in Madagascar

    NASA Astrophysics Data System (ADS)

    N, Rabesiranana; M, Rasolonirina; F, Solonjara A.; Andriambololona., Raoelina; L, Mabit

    2010-05-01

    The region of Vinaninkarena located in central Madagascar (47°02'40"E, 19°57'17"S), is known to be a high natural radioactive area. Uranium ore was extracted in this region during the 1950s and the early 1960s. In the mid-1960s, mining activities were stopped and the site abandoned. In the meantime, the region, which used to be without any inhabitants, has recently been occupied by new settlers with presumed increase in exposure of the local population to natural ionizing radiation. In order to assess radiological risk, a survey to assess the soil natural radioactivity background was conducted during the year 2004. This study was implemented in the frame of the FADES Project SP99v1b_21 entitled: Assessment of the environmental pollution by multidisciplinary approach, and the International Atomic Energy Agency Technical Cooperation Project MAG 7002 entitled: Effects of air and water pollution on human health. Global Positioning System (GPS) was used to determine the geographical coordinates of the top soil samples (0-15cm) collected. The sampling was performed using a multi integrated scale approach to estimate the spatial variability of the parameters under investigation (U, Th and K) using geo-statistical approach. A total of 205 soil samples was collected in the study site (16 km2). After humidity correction, the samples were sealed in 100 cm3 cylindrical air-tight plastic containers and stored for more than 6 months to reach a secular equilibrium between parents and short-lived progeny (226Ra and progeny, 238U and 234Th). Measurements were performed using a high-resolution HPGe Gamma-detector with a 30% relative efficiency and an energy resolution of 1.8 keV at 1332.5 keV, allowing the determination of the uranium and thorium series and 40K. In case of secular equilibrium, a non-gamma-emitting radionuclide activity was deduced from its gamma emitting progeny. This was the case for 238U (from 234Th), 226Ra (from 214Pb and 214Bi) and 232Th (from 228Ac, 212Pb or

  12. Determination of gross alpha, 224Ra, 226Ra, and 228Ra activities in drinking water using a single sample preparation procedure.

    PubMed

    Parsa, Bahman; Obed, Reynaldo N; Nemeth, William K; Suozzo, Gail P

    2005-12-01

    The current federal and New Jersey State regulations have greatly increased the number of gross alpha and radium tests for public and private drinking water supplies. The determination of radium isotopes in water generally involves lengthy and complicated processes. In this study, a new approach is presented for the determination of gross alpha, 224Ra, 226Ra, and 228Ra activities in water samples. The method includes a single sample preparation procedure followed by alpha counting and gamma-ray spectroscopy. The sample preparation technique incorporates an EPA-approved co-precipitation methodology for gross alpha determination with a few alterations and improvements. Using 3-L aliquots of sample, spiked with 133Ba tracer, the alpha-emitting radionuclides are isolated by a BaSO4 and Fe(OH)3 co-precipitation scheme. First the gross alpha-particle activity of the sample is measured with a low-background gas-flow proportional counter, followed by radium isotopes assay by gamma-ray spectroscopy, using the same prepared sample. Gamma-ray determination of 133Ba tracer is used to assess the radium chemical recovery. The 224Ra, 226Ra, and 228Ra activities in the sample are measured through their gamma-ray-emitting decay products, 212Pb, 214Pb/214Bi, and 228Ac, respectively. In cases where 224Ra determination is required, the gamma-ray counting should be performed within 2-4 d from sample collection. To measure 226Ra activity in the sample, the gamma-ray spectroscopy can be repeated 21 d after sample preparation to ensure that 226Ra and its progeny have reached the equilibrium state. At this point, the 228Ac equilibration with parent 228Ra is already established. Analysis of aliquots of de-ionized water spiked with NIST-traceable 230Th, 224Ra, 226Ra, and 228Ra standards demonstrated the accuracy and precision of this method. Various performance evaluation samples were also assayed for gross alpha as well as radium isotope activity determination using this procedure and the

  13. The COBRA Double Beta Decay Experiment

    NASA Astrophysics Data System (ADS)

    Dawson, J. V.

    2007-03-01

    The progress of the COBRA neutrinoless double beta decay experiment is discussed. Potential backgrounds are described. Estimates on the contamination levels of 214Bi in the detectors have been made using previously acquired low background data. New crystals with a different passivation material show an improved background count rate of approximately one order of magnitude.

  14. The COBRA Double Beta Decay Experiment

    SciTech Connect

    Dawson, J. V.

    2007-03-28

    The progress of the COBRA neutrinoless double beta decay experiment is discussed. Potential backgrounds are described. Estimates on the contamination levels of 214Bi in the detectors have been made using previously acquired low background data. New crystals with a different passivation material show an improved background count rate of approximately one order of magnitude.

  15. A radiometric and petrographic approach to risk assessment at Alte Madonie Mounts region (Sicily, Italy).

    PubMed

    Lanzo, G; Rizzo, S; Tomarchio, E

    2014-03-01

    The main goal of this work was to assess the radiological hazard at Alte Madonie Mounts region (north-central Sicily, Italy) in response to rumours of an increase in the incidence of cancer in this area. A correlation between the natural radionuclide contents and the petrographic features of the soil and rock samples was also evaluated. A total of 41 samples of selected soils and rocks were collected, powdered, dried and sealed in 'Marinelli' beakers for 20 d prior to measurement to ensure that a radioactive equilibrium between (226)Ra and (214)Bi had been reached. A gamma-ray spectrometer was used to quantify the radioactivity concentrations. To determine (238)U and (232)Th activities, the 609.3-keV line from (214)Bi in secular equilibrium with (226)Ra and the 911-keV line from (228)Ac, with which (232)Th can be assumed to be in equilibrium, were used, respectively. The gamma transition of 1461 keV was used to determine (40)K activity. The average values of the concentrations of (214)Bi, (228)Ac and (40)K were 30, 17 and 227 Bq kg(-1), respectively, whereas the greatest values were 134, 59 and 748 Bq kg(-1), respectively. A linear relationship was found between the activity values of (214)Bi, (228)Ac and (40)K. An exception was found for a group of samples in which the (214)Bi activities were much higher than expected. The chemical compositions and mineralogical features of the samples permitted the justification of these anomalies. The results of the primordial radionuclide contents are reassuring from a radiation protection point of view because the activities of the uranium and thorium series products and of the (40)K do not present a significant radiological hazard. PMID:24106332

  16. Influences of vertical transport and scavenging on aerosol particle surface area and radon decay product concentrations at the Jungfraujoch (3454 m above sea level)

    NASA Astrophysics Data System (ADS)

    Lugauer, M.; Baltensperger, U.; Furger, M.; GäGgeler, H. W.; Jost, D. T.; Nyeki, S.; Schwikowski, M.

    2000-08-01

    Concentrations of the aerosol particle surface area (SA) and aerosol-attached radon decay products 214Pb and 212Pb have been measured by means of an aerosol and a radon epiphaniometer at the Jungfraujoch research station (JFJ; 3454 m above sea level, Switzerland). These parameters exhibit a pronounced seasonal cycle with minimum values in winter and maximum values in summer. In summer, pronounced diurnal variations with a maximum at 1800 LST are often present. Highest concentrations and most pronounced diurnal variations occur during anticyclonic weather conditions in summer. Thermally driven vertical transport over alpine topography is responsible for this observation. During this synoptic condition, concentrations vary greatly with the 500 hPa wind direction, exhibiting low concentrations for NW-N winds and high concentrations for weak or S-SW winds. Lead-214 and SA are highly correlated during anticyclonic conditions, indicating transport equivalence of the gaseous 214Pb precursor, 222Rn, and of aerosol particles. When cyclonic lifting is the dominant vertical transport, wet scavenging of aerosol particles can explain the weak correlation of 214Pb and SA. This conclusion is corroborated by the 214Pb/SA ratio, being twice as high during cyclonic than during anticyclonic conditions. Lead-212 is a tracer for the influence of surface contact on a local scale due to its short lifetime of 15.35 hours. The analysis of this parameter suggests that high-alpine surfaces play an important role in thermally driven transport to the JFJ.

  17. Seasonal variations of aerosol residence time in the lower atmospheric boundary layer.

    PubMed

    Ahmed, A A; Mohamed, A; Ali, A E; Barakat, A; Abd El-Hady, M; El-Hussein, A

    2004-01-01

    During a one year period, from Jan. 2002 up to Dec. 2002, approximately 130 air samples were analyzed to determine the atmospheric air activity concentrations of short- and long-lived (222Rn) decay products 214Pb and 210Pb. The samples were taken by using a single-filter technique and gamma-spectrometry was applied to determine the activity concentrations. A seasonal fluctuation in the concentration of 214Pb and 210Pb in surface air was observed. The activity concentrations of both radionuclides were observed to be relatively higher during the winter/autumn season than in spring/summer season. The mean activity concentration of 214Pb and 210Pb within the whole year was found to be 1.4+/-0.27 Bq m(-3) and 1.2+/-0.15 mBq m(-3), respectively. Different 210Pb:214Pb activity ratios during the year varied between 1.78 x 10(-4) and 1.6 x 10(-3) with a mean value of 8.9 x 10(-4) +/- 7.6 x 10(-5). From the ratio between the activity concentrations of the radon decay products 214Pb and 210Pb a mean residence time (MRT) of aerosol particles in the atmosphere of about 10.5+/-0.91 d could be estimated. The seasonal variation pattern shows relatively higher values of MRT in spring/summer season than in winter/autumn season. The MRT data together with relative humidity (RH), air temperature (T) and wind speed (WS), were used for a comprehensive regression analysis of its seasonal variation in the atmospheric air. PMID:15381321

  18. Deposition of {open_quotes}unattached{close_quotes} radon daughters in models of human nasal and oral airways

    SciTech Connect

    Strong, J.C.; Swift, D.L.

    1992-12-31

    In order to estimate accurately an effective dose equivalent for exposures to radon daughters, knowledge of their deposition in the lung is required. However, the nose and mouth are effective filters for removing aerosol particles, especially in the range of sizes of {open_quotes}unattached{close_quotes} radon daughters. Therefore, it is equally important to have reliable data on deposition in this region of the respiratory tract. We will describe our work in studying nasal and oral deposition of {open_quotes}unattached{close_quotes} radon daughters in casts of these airways. Several hollow casts of adult and child nasal and oral airways were fabricated at The John Hopkins University from layers of Perspect{trademark} (an acrylic plastic). The shapes of the airway passages were obtained from nuclear magnetic resonance sectional images of healthy subjects. The casts were exposed to radon gas and daughters produced by flushing filtered air through a commercially available {sup 226}Ra source. The gas stream was drawn through a 1.4-L cylindrical tube to allow measurable growth of {sup 218}Po activity before it was passed through casts of both nasal passages or the oral cavity. The deposition of {open_quotes}unattached{close_quotes} {sup 218}Po was measured by comparing the activity collected on filters mounted in series and in parallel with a cast. Measurements were made at various flow rates (Q; 4 to 20 L min{sup -1}). The diffusion coefficient (D) of {sup 218}Po was measured each time the flow rate was changed, by replacing the cast with a stainless steel gauze screen and measuring the activity penetrating the screen. The measured diffusion coefficient ranged from 0.02 to 0.05 cm{sup 2} s{sup -1} and was found to vary with the residence time of {sup 218}Po in the growth tube. The deposition efficiency ({eta}) of {sup 218}Po measured in these casts ranged from 50 to 70%, and was similar to values we found previously, using casts of nasal and oral airways from cadavers.

  19. Measuring the activity of inhaled ²²²Rn using a lung counting system.

    PubMed

    Zhiwei, Cheng; Mingyan, Jia; Maoquan, Shen

    2015-02-01

    A new method of directly measuring (222)Rn progeny in a worker's lung using a lung counting system is introduced. To determine the efficiency of the lung counting system, a torso phantom manufactured by the China Institute for Radiation Protection was used, where activated carbon that had been loaded in a radon chamber with a defined quantity of radon represented the lungs, which were usually made of urethane foam. The minimum detectable activity (MDA) of (214)Bi, one of the (222)Rn progenies, was estimated to be 7.3 Bq for a measurement time of 4000 s. Based on the time (222)Rn progenies stay in the lung, it may be concluded that the lung counting system described can be well used for directly measuring the activity of (214)Bi in the lung short time after a worker inhaled (222)Rn at his/her workplace. PMID:24803514

  20. The BiPo low-background detector project

    NASA Astrophysics Data System (ADS)

    Vasilyev, R. V.

    2009-05-01

    A low-background detector designed to search for weak radioactive pollution by 208Tl and 214Bi in thin samples of a large area is described. The samples are 12-m2 source foils made of 82Se or 150Nd enriched isotopes. Such samples are planned for use in investigating neutrinoless double β decay in the SuperNEMO experiment. The principle of the detector operation is based on registering the delayed β-α coincidence from the uranium and thorium radioactive chains. The sensitivity of the detector is planned to be at the level of 208Tl < 2 μBq/kg and 214Bi < 10 μBq/kg. Alternate versions of the detector are described. The first results obtained by the prototype detector, operated in the Frejus Underground Laboratory in France, are presented.

  1. Gamma-spectrometric uranium age-dating using intrinsic efficiency calibration

    NASA Astrophysics Data System (ADS)

    Nguyen, Cong Tam; Zsigrai, József

    2006-01-01

    A non-destructive, gamma-spectrometric method for uranium age-dating is presented which is applicable to material of any physical form and geometrical shape. It relies on measuring the daughter/parent activity ratio 214Bi/234U by low-background, high-resolution gamma-spectrometry using intrinsic efficiency calibration. The method does not require the use of any reference materials nor the use of an efficiency calibrated geometry.

  2. Measurements of Pb-212 and Pb-214 in surface air around Lake Michigan and their implications for atmospheric boundary layer mixing

    NASA Astrophysics Data System (ADS)

    Aquino, Nadja Wackerling

    1997-10-01

    The dynamics of the atmospheric boundary layer are a result of turbulence generated at the Earth's surface. The extent of mixing in the boundary layer is studied by using radionuclides as tracers under different conditions such as: wind direction dependent on passing synoptic systems, upwind and downwind lake shore sites, urban versus rural setting, and urban setting at two different altitudes. Data were collected by high volume air samplers at each site, which filtered air for day and night intervals several days in a row. The filters were placed in a GeLe detector and gamma rays of 212Pb and 214Pb decays were counted. From these measurements, the concentrations of 212Pb and 214Pb in the sampled air were determined. Among the types of radionuclide behavior are diurnal variation in activities, synoptic-scale variation, variation due to different surface roughness characteristics and position with respect to the wind at the lake shore, and limited variation in activity at high altitude at the urban site. A series of one dimensional models were developed to interpret the data. The horizontal advection model predicted the effect on 212Pb and 214Pb activities of advecting air over a 100 km zero source region at constant velocity. 212Pb activities decrease substantially for velocities greater than 1 m/s, whereas 214Pb does not decrease much until velocities reach 100 m/s. The vertical diffusion model predicted 212Pb and 214Pb vertical profiles for different vertical diffusivities, κ z. A one order of magnitude change in κ z produces a /sqrt[10] change in activity in surface air. The results of both models are equivalent for 212Pb activities. Comparing 212Pb and 214Pb, vertical mixing affects both radionuclides similarly, but horizontal advection fractionates the two radionuclides. The diurnal box models predict activities an order of magnitude lower than the steady state models, in close agreement with observations. Furthermore, an order of magnitude increase can

  3. Potential for ion-induced nucleation of volatile organic compounds by radon decay in indoor environments

    SciTech Connect

    Daisey, J.M.

    1991-11-01

    There is considerable interest in the ``unattached`` fraction of radon progeny in indoor air because of its significance to the estimation of the risks of radon exposure. Because of its high mobility in air, the unattached fraction is more efficiently deposited in the respiratory tract. Variation in the diameter of the ``unattached`` fraction and in its diffusion coefficient can be due to clustering of other atmospheric species around the {sup 218}PoO{sub 2}{sup +} ion. The purpose of this study was to investigate the potential for the formation of clusters of vapor phase organic compounds, found in indoor air, around the {sup 218}PoO{sub 2}{sup +} ion and to determine which were most likely to form clusters. A secondary purpose was to provide a compilation of measurements of indoor organic compounds for future experiments and theoretical calculations by the radon research community. The classical charged liquid droplet theory (Thomson equation) was used to estimate the Gibbs free energy of ion-induced nucleation and to provide an indication of the indoor organic compounds most likely to undergo ion-induced nucleation. Forty-four volatile and semi-volatile organic compounds out of the more than 300 which have been reported in indoor air were investigated. Water vapor was included for comparison. The results indicate that there is a potential for the formation of clusters of organic compounds around the {sup 218}PoO{sub 2}{sup +} ion. The compounds with the greatest potential for cluster formation are the volatile oxidized hydrocarbons (e.g., n-butanol, phenol, hexanal, nonanal, benzaldehyde, the ketones and the acetates) and the semi-volatile organic compounds (pentachlorophenol, nicotine, chlordane, chlorpyrifos).

  4. Potential for ion-induced nucleation of volatile organic compounds by radon decay in indoor environments

    SciTech Connect

    Daisey, J.M.

    1991-11-01

    There is considerable interest in the unattached'' fraction of radon progeny in indoor air because of its significance to the estimation of the risks of radon exposure. Because of its high mobility in air, the unattached fraction is more efficiently deposited in the respiratory tract. Variation in the diameter of the unattached'' fraction and in its diffusion coefficient can be due to clustering of other atmospheric species around the {sup 218}PoO{sub 2}{sup +} ion. The purpose of this study was to investigate the potential for the formation of clusters of vapor phase organic compounds, found in indoor air, around the {sup 218}PoO{sub 2}{sup +} ion and to determine which were most likely to form clusters. A secondary purpose was to provide a compilation of measurements of indoor organic compounds for future experiments and theoretical calculations by the radon research community. The classical charged liquid droplet theory (Thomson equation) was used to estimate the Gibbs free energy of ion-induced nucleation and to provide an indication of the indoor organic compounds most likely to undergo ion-induced nucleation. Forty-four volatile and semi-volatile organic compounds out of the more than 300 which have been reported in indoor air were investigated. Water vapor was included for comparison. The results indicate that there is a potential for the formation of clusters of organic compounds around the {sup 218}PoO{sub 2}{sup +} ion. The compounds with the greatest potential for cluster formation are the volatile oxidized hydrocarbons (e.g., n-butanol, phenol, hexanal, nonanal, benzaldehyde, the ketones and the acetates) and the semi-volatile organic compounds (pentachlorophenol, nicotine, chlordane, chlorpyrifos).

  5. Apparatus for the Measurement of {sup 222}Rn Diffusion

    SciTech Connect

    Mamedov, F.; Konicek, J.; Stekl, I.

    2009-11-09

    A new apparatus for the measurement of {sup 222}Rn diffusion through shielding foils developed in the frame of the NEMO collaboration is briefly described. The setup is based on the electrostatic collection of radon progenies {sup 218}Po and {sup 214}Po. The NEMO project is an underground experiment for the study of double beta decay processes. For such type of experiments the efficient suppression of background caused by radon is essential. The first test of the apparatus has been carried out using Penefol foil (0.8 mm thickness) and the suppression factor of radon concentration has been obtained.

  6. Early onset of deformation in the neutron-deficient polonium isotopes

    NASA Astrophysics Data System (ADS)

    Cocolios, T. E.; Andreyev, A. N.; Antalic, S.; Barzakh, A. E.; Bastin, B.; Büscher, J.; Darby, I. G.; Dexters, W.; Fedorov, D. V.; Fedosseev, V. N.; Flanagan, K. T.; Franchoo, S.; Fritzsche, S.; Huber, G.; Huyse, M.; Keupers, M.; Köster, U.; Kudryavtsev, Yu; Mané, E.; Marsh, B. A.; Molkanov, P. L.; Page, R. D.; Seliverstov, M. D.; Sjödin, A. M.; Stefan, I.; Van de Walle, J.; Van Duppen, P.; Venhart, M.; Zemlyanoy, S. G.

    2012-09-01

    In-source laser spectroscopy has been performed at CERN-ISOLDE with the RILIS laser ion source on 191-204,206,208-211,216,218Po. New information on the β decay of 199Po were extracted in the process, challenging previous results. Large-scale atomic calculations were performed to extract the changes in the mean-square charge radius δlangler2rangle from the isotope shifts. The δlangler2rangle for the even-A isotopes reveal a large deviation from the spherical droplet model for N < 116.

  7. Quantitative analysis of gamma-ray emitters radioisotopes in commercialised bottled water in Tunisia.

    PubMed

    Ben Fredj, A; Hizem, N; Chelbi, M; Ghedira, L

    2005-01-01

    A set of measurements have been conducted in order to determine the annual effective dose resulting from the ingestion of natural radionuclides present in eight different brands of bottled water commercialised in Tunisia. Using high-resolution gamma spectrometry technique, we have noted the presence of the following radionuclides: 214Bi, 226Ra, 228Ac, 212Pb, 235U and 40K. For all classes of age, only the radium concentration was found to be significant in the calculation of the equivalent dose. Some of the studied samples exceeded the reference level of 0.1 mSv y(-1) of effective dose. PMID:15985499

  8. Measurements of natural radioactivity inside dandara temple

    NASA Astrophysics Data System (ADS)

    Ahmed, N. K.; Saied, M. H.; Abbady, A.; El-Kamel, A. H.

    1994-07-01

    The natural radioactivities inside Dandara temple are studied by using a NaI(Tl) scintillation spectrometer. The variation of these activities with location is investigated. Average values of the identified radionuclides inside the halls, sanctuary and crypt of the temple are examined. It is estimated that the mean value lies in the range 37.9-90.1 for 212Pb, 70.0-36.0 for 214Bi, 52.6-76.2 for 228Ac, 1.6-5.9 for 208Tl, while for 40K it is 169.3-286.6.

  9. Seabed radioactivity based on in situ measurements and Monte Carlo simulations.

    PubMed

    Androulakaki, E G; Tsabaris, C; Eleftheriou, G; Kokkoris, M; Patiris, D L; Vlastou, R

    2015-07-01

    Activity concentration measurements were carried out on the seabed, by implementing the underwater detection system KATERINA. The efficiency calibration was performed in the energy range 350-2600 keV, using in situ and laboratory measurements. The efficiency results were reproduced and extended in a broadened range of energies from 150 to 2600 keV, by Monte Carlo simulations, using the MCNP5 code. The concentrations of (40)K, (214)Bi and (208)Tl were determined utilizing the present approach. The results were validated by laboratory measurements. PMID:25846455

  10. Levels of sup 137 Cs and natural radioactivity in Saudi Arabian soil

    SciTech Connect

    Abulfarai, W.; Abdul-Majid, S. )

    1991-01-01

    After the Chernobyl accident, there was concern about contamination from the radioactive plume reaching Saudi Arabia. Cesium-137 concentration in the soil was measured to determine the degree of contamination from the accident. The concentrations of {sup 40}K, {sup 214}Bi, and {sup 228}Ac were determined as well. Bismuth-214 is a member of the {sup 238}U series, while {sup 228}Ac is from the {sup 238}Th series. Each of these isotopes emits several well-resolved photons of relatively high intensity per disintegration.

  11. Characterization of Radon Progeny in EXO-200 Using Machine Learning Algorithms

    NASA Astrophysics Data System (ADS)

    Smith, Erica

    Neutrinoless double beta decay (0nubetabeta) is a rare, second-order process that occurs in certain isotopes for which beta decay is energetically forbidden. EXO-200 is a 0nubetabeta experiment with 110 kg of active liquid xenon (LXe) isotopically enriched in 136Xe. EXO-200 detects events using a combination of scintillation and ionization signals, which allows for excellent particle discrimination. However, events with a low ionization signal cannot be fully characterized with the current analysis framework. To fill in these gaps, we introduce a boosted decision tree regressor as a new tool to characterize events in the detector. We focus on alpha decays of 222Rn and its progeny, which have low ionization signals that often fall below the threshold for position reconstruction. Using information gained from this technique, we confirm previous results for the 218Po ion velocity and improve previous results for the 218Po ionization fraction. We also investigate events that occur near the walls of the vessel. These events have no ionization signal and therefore cannot be characterized with any existing technique in the analysis framework. By investigating these events we determine that they are not distributed uniformly throughout the detector, which may point to charging up of the plastics inside the LXe vessel or a "hot spot'' on the plastic due to contamination during cleaning and installation.

  12. Study on peak shape fitting method in radon progeny measurement.

    PubMed

    Yang, Jinmin; Zhang, Lei; Abdumomin, Kadir; Tang, Yushi; Guo, Qiuju

    2015-11-01

    Alpha spectrum measurement is one of the most important methods to measure radon progeny concentration in environment. However, the accuracy of this method is affected by the peak tailing due to the energy losses of alpha particles. This article presents a peak shape fitting method that can overcome the peak tailing problem in most situations. On a typical measured alpha spectrum curve, consecutive peaks overlap even their energies are not close to each other, and it is difficult to calculate the exact count of each peak. The peak shape fitting method uses combination of Gaussian and exponential functions, which can depict features of those peaks, to fit the measured curve. It can provide net counts of each peak explicitly, which was used in the Kerr method of calculation procedure for radon progeny concentration measurement. The results show that the fitting curve fits well with the measured curve, and the influence of the peak tailing is reduced. The method was further validated by the agreement between radon equilibrium equivalent concentration based on this method and the measured values of some commercial radon monitors, such as EQF3220 and WLx. In addition, this method improves the accuracy of individual radon progeny concentration measurement. Especially for the (218)Po peak, after eliminating the peak tailing influence, the calculated result of (218)Po concentration has been reduced by 21 %. PMID:25920795

  13. Environmental neutralization of polonium-218

    SciTech Connect

    Goldstein, S.D.; Hopke, P.K.

    1985-01-01

    Previous work has indicated that two mechanisms of neutralization of the singly charged polonium ion exist. Charged Polonium-218 can be neutralized by reacting with oxygen to form a polonium oxide ion with a higher ionization potential than that of the polonium metal and then accepting an electron transferred from a lower ionization potential gas. In this present work, this mechanism has been verified by determining that the polonium oxide has an ionization potential in the range 10.35-10.53 eV. It was also previously reported that /sup 218/Po can be neutralized, in the absence of oxygen, by the scavenging of electrons by a trace gas such as water or nitrogen dioxide and their diffusion to the polonium ion. To verify this second neutralization mechanism, concentrations of nitrogen dioxide in nitrogen in the range of 50 ppb-1 ppm were examined for their ability to neutralize the polonium ion. Complete neutralization of /sup 218/Po was observed at nitrogen dioxide concentrations greater than 700 ppb. For concentrations below 700 ppb, the degree of neutralization was found to increase smoothly with the nitrogen dioxide concentration.

  14. The CDF top search in the multijet decay mode

    SciTech Connect

    Denby, B.; CDF Collaboration

    1994-01-01

    A status report on the CDF top search in the multijet channel is given. After topological cuts and the requirement of a secondary vertex in the silicon microvertex detector, about 120 events remain (21.4 pb{sup {minus}1}), in which the signal to background ratio (for a nominal top mass of 160 GeV) is estimated to be 1/10. With further improvements it should be possible to improve this ratio to 1/1 while retaining good efficiency for top, which will make the multijet channel an important cross check for the leptonic modes.

  15. Environmental Radioactivity Study in Surface Sediments of Guacanayabo Gulf (Cuba)

    SciTech Connect

    Reyes, H.; Rizo, O. Diaz; Bernal, J. L.; D'Alessandro, K.; Padilla, F.; Corrales, Y.; Casanova, O. A.; Gelen, A.; Martinez, Y.; Aguilar, J.; Arado, J. O.; Lopez-Pino, N.; Maidana, N. L.

    2009-06-03

    Sediment samples have been collected in the Guacanayabo gulf located in the southeast Cuba, to determinate the radioactivity levels of {sup 210}Pb, {sup 234}Th, {sup 214}Pb, {sup 137}Cs, {sup 232}Th and {sup 40}K using Low-Background Gamma Spectrometry and to evaluate its impact in the habitat of important marine species for fishery industry. The obtained results show the lowest radioactivity levels determined in Cuban marine environments. The species capture declination in the last years is not originated by radioactive pollution of the zone.

  16. Activity standardisation of ²²⁶Ra by 4πα liquid scintillation counting method.

    PubMed

    Havelka, Miroslav; Bluďovský, Richard

    2013-11-01

    Activity of (226)Ra in radium daughter products free solution was determined by 4πα liquid scintillation counting (LSC) method, where the detection efficiency of radium decay is practically equal to 1. The sources were prepared from solution with known (226)Ra mass concentration, from which, immediately before LS counting, (222)Rn and its daughter nuclides were removed by solvent extraction. LS counting results were corrected practically only for a <0.6% loss of radium from measured sample and for the ingrowth of (222)Rn and (218)Po concentrations in the sample after the separation was completed. The combined relative standard uncertainty was estimated to be lower than 0.34%. PMID:23602705

  17. Energy deposition and radiation quality of radon and radon daughters. Final report

    SciTech Connect

    Karam, L.R.; Caswell, R.S.

    1996-09-09

    This program was aimed at creating a quantitative physical description, at the micrometer and nanometer levels, of the physical interactions of the alpha particles from radon and its daughters with cells at risk in the bronchial epithelium. The authors calculated alpha-particle energy spectra incident upon the cells and also energy deposition spectra in micrometer- and nanometer-sized sites as a function of cell depth, site size, airway diameter, activities of {sup 218}Po and {sup 214}Po, and other parameters. These data are now being applied, using biophysical models of radiation effects, to predict cell killing, mutations, and cell transformation. The model predictions are then compared to experimental biophysical, biochemical, and biological information. These studies contribute to a detailed understanding of the mechanisms of the biological effectiveness of the radiations emitted by radon and its progeny.

  18. A micromegas detector for {sup 222}Rn emanations measurements

    SciTech Connect

    García, J. A.; Garza, J. G.; Irastorza, I. G.; Mirallas, H.

    2013-08-08

    The {sup 222}Rn emanation has significant contribution in the overall background for rare event searches experiments. In order to measure this emanations a high sensitivity detector has been designed. The detection method is based on the electrostatic collection of the {sup 222}Rn daughters on a Micromegas detector. Using a chamber with a volume of 21.2 l for the collection of {sup 218}Po and {sup 214}Po progeny of {sup 222}Rn and a 12 × 12cm{sup 2} pixelized Micromegas for the α detection. The advantages of the Micromegas detectors are the low intrinsic radioactivity and the track reconstruction of the α’s, having excellent capabilities for event discrimination.

  19. An electrostatic integrating 222Rn monitor with cellulose nitrate film for environmental monitoring.

    PubMed

    Iida, T; Ikebe, Y; Hattori, T; Yamanishi, H; Abe, S; Ochifuji, K; Yokoyama, S

    1988-02-01

    This paper describes a new type of electrostatic integrating 222Rn monitor designed for the environmental 222Rn monitoring. The window area of the monitor was selected to make the exchange rate optimal. The collecting electrode was positioned on the basis of calculating the internal electric field. A drying agent, P2O5, was placed in the bottom of the monitor, since the collection efficiency of 218Po+ atoms depends on the humidity of the air. The monitors have been calibrated against known 222Rn exposures. The detection limit is 1.2 Bq m-3 for an exposure time of 2 mo. In a small survey, annual mean 222Rn concentrations between 3.7 and 9.5 Bq m-3 in outdoor air and between 6.4 and 11.9 Bq m-3 in indoor air were measured. PMID:3338911

  20. A novel algorithm for quick and continuous tracing the change of radon concentration in environment

    NASA Astrophysics Data System (ADS)

    Tan, Yanliang; Xiao, Detao

    2011-04-01

    Several measurements of the radon concentration are performed by RAD7 in the University of South China. We find that 30-40 min is needed for RAD7 for tracing the concentration of the standard radon chamber. There are two reasons. The first is that the sufficient time of air cycle is needed for the radon concentration in internal cell of RAD7 equal to that of the environment; and the second is that the sufficient decay time is needed for the 218Po concentration in internal cell of RAD7 equal to that of the radon. We used a zeroth order approximation to describe the evolution of the environment radon concentration, and obtained a novel algorithm for quick and continuous tracing the change of radon concentration. The corrected radon concentration obtained through this method is in good agreement with the reference value. This method can be applied to develop and improve the instruments for tracing the change of radon concentration quickly.

  1. Early Onset of Ground State Deformation in Neutron Deficient Polonium Isotopes

    SciTech Connect

    Cocolios, T. E.; Van de Walle, J.; Dexters, W.; Bastin, B.; Buescher, J.; Darby, I. G.; Huyse, M.; Keupers, M.; Kudryavtsev, Yu.; Van Duppen, P.; Seliverstov, M. D.; Andreyev, A. N.; Antalic, S.; Barzakh, A. E.; Fedorov, D. V.; Molkanov, P. L.; Fedosseyev, V. N.; Marsh, B. A.; Flanagan, K. T.; Franchoo, S.

    2011-02-04

    In-source resonant ionization laser spectroscopy of the even-A polonium isotopes {sup 192-210,216,218}Po has been performed using the 6p{sup 3}7s {sup 5}S{sub 2} to 6p{sup 3}7p {sup 5}P{sub 2} ({lambda}=843.38 nm) transition in the polonium atom (Po-I) at the CERN ISOLDE facility. The comparison of the measured isotope shifts in {sup 200-210}Po with a previous data set allows us to test for the first time recent large-scale atomic calculations that are essential to extract the changes in the mean-square charge radius of the atomic nucleus. When going to lighter masses, a surprisingly large and early departure from sphericity is observed, which is only partly reproduced by beyond mean field calculations.

  2. Characterisation of an electronic radon gas personal dosemeter.

    PubMed

    Gründel, M; Postendörfer, J

    2003-01-01

    The monitoring of radon exposure at workplaces is of great importance. Up to now passive measurement systems have been used for the registration of radon gas. Recently an electronic radon gas personal dosemeter came onto the market as an active measurement system for the registration of radon exposure (DOSEman; Sarad GmbH, Dresden, Germany). In this personal monitor, the radon gas diffuses through a membrane into a measurement chamber. A silicon detector system records spectroscopically the alpha decays of the radon gas and of the short-lived progeny 218Po and 214Po gathered onto the detector by an electrical field. In this work the calibration was tested and a proficiency test of this equipment was made. The diffusion behaviour of the radon gas into the measurement chamber, susceptibility to thoron, efficiency, influence of humidity, accuracy and the detection limit were checked. PMID:14756187

  3. An optimized system for measurement of radon levels in buildings by spectroscopic measurement of radon progeny

    NASA Astrophysics Data System (ADS)

    Fröjdh, A.; Thungström, G.; Fröjdh, C.; Petersson, S.

    2011-12-01

    Radon gas, 222Rn, is a problem in many buildings. The radon gas is not harmful in itself, but the decay chain contains charged elements such as 218Po, and 214Po ions which have a tendency to stick to the lungs when inhaled. Alpha particles from the decay of these ions cause damages to the lungs and increase the risk of lung cancer. The recent reduction in the limits for radon levels in buildings call for new simple and efficient measurement tools [1]. The system has been optimized through modifications of the detector size, changes to the filters and the design of the chamber. These changes increase the electric field in the chamber and the detection efficiency.

  4. Study of the atmospheric chemistry of radon progeny in laboratory and real indoor atmospheres. Final project report

    SciTech Connect

    Hopke, P.K.

    1996-09-01

    This report completes Clarkson University`s study of the chemical and physical behavior of the {sup 218}Po atom immediately following its formation by the alpha decay of radon. Because small changes in size for activity in the sub-10 nm size range result in large changes in the delivered dose per unit exposure, this behavior must be understood if the exposure to radon progeny and it dose to the cells in the respiratory tract are to be fully assessed. In order to pursue this general goal, two areas of radon progeny behavior are being pursued; laboratory studies under controlled conditions to better understand the fundamental physical and chemical processes that affect the progeny`s atmospheric behavior and studies in actual indoor environments to develop a better assessment of the exposure of the occupants of that space to the size and concentration of the indoor radioactive aerosol. Thus, two sets of specific goals have been established for this project. The specific tasks of the controlled laboratory studies are (1) Determine the formation rates of {circ}OH radicals formed by the radiolysis of air following radon decay; (2) Examine the formation of particles by the radiolytic oxidation of substances like SO{sub 2}, ethylene, and H{sub 2}S to lower vapor pressure compounds and determine the role of gas phase additives such as H{sub 2}O and NH{sub 3} in determining the particle size; (3) Measure the rate of ion-induced nucleation using a thermal diffusion cloud chamber, and (4) Measure the neutralization rate of {sup 218}PoO{sub x}{sup +} in O{sub 2} at low radon concentrations.

  5. Simultaneous determination of 226Ra, 233U and 237Np by liquid scintillation spectrometry.

    PubMed

    Nebelung, Cordula; Baraniak, Lutz

    2007-02-01

    A method has been developed for the simultaneous determination of 226Ra, 233U and 237Np by liquid-scintillation (LS) spectrometry. This method consists of the evaluation of the alpha-spectrum that is composed of the strongly overlapping peaks of 226Ra, 233U, 237Np, 222Rn and 218Po in the energy range of 4.60-6.00 MeV and the single 214Po peak at 7.69 MeV. The alpha-peaks are analysed by a special peak fit function that considers the deviation of the alpha-peak at the low energy side from the pure Gaussian shape. First 237Np is determined using its daughter 233Pa by analysing the beta-spectrum in the range 150-570 keV. 226Ra follows from the alpha-spectrum that is measured 6 weeks after sample preparation, i.e., 226Ra is determined from the radioactive equilibrium with its short-lived daughters 222Rn, 218Po and 214Po. Finally the 233U activity results from the fitted spectrum in the range of 4.4-4.8 MeV by subtracting the activity of 226Ra and 237Np. Knowing the exact energy position of the LS-peaks an alternative evaluation consists in the accurate deconvolution of the first three peaks that are formed by 226Ra and 233U (maximum of both at channel 700), 237Np (maxima at channels 700 and 725) and 222Rn (maximum at channel 737). In these two ways 226Ra, 233U and 237Np can be determined in mutual activity ratios of 1:50 with a relative standard deviation of less than 4% for the major activity and 9% for the minor activity. PMID:17142052

  6. Study of the atmospheric chemistry of radon progeny in laboratory and real indoor atmospheres

    SciTech Connect

    Hopke, P.K.

    1992-07-01

    This report describes studies on the chemical and physical behavior of the [sup 218]Po atom immediately following its formation by the alpha decay of radon. Because small changes in size for activity in the sub-10 nm size range result in large changes in the delivered dose per unit exposure, this behavior must be understood if the exposure to radon progeny and its dose to the cells in the respiratory tract are to be fully assessed. The specific tasks of the controlled laboratory studies are to determine the formation rates of [center dot]OH radicals formed by the radiolysis of air following radon decay, to examine the formation of particles by the radiolytic oxidation of substances like SO[sub 2] ethylene, and H[sub 2]S to lower vapor pressure compounds and determine the role of gas phase additives such as H[sub 2]O and NH[sub 3] in determining the particle size, to measure the rate of ion-induced nucleation using a thermal diffusion cloud chamber, and to measure the neutralization rate of [sup 218]Po[sub x][sup +] in O[sub 2] at low radon concentrations. Tasks of the exposure studies in occupied indoor spaces are to initiate measurements of the activity size distributions in actual homes with occupants present so that the variability of the indoor activity size distributions can be assessed with respect to indoor aerosol sources and general lifestyle variations of the occupants, to initiate a prospective study of the utility of measurement of deposited [sup 210]Pb embedded in glass surfaces as a measure of the long-term, integrated exposure of the population to radon, and to develop the methodology to determine the hygroscopicity of the indoor aerosol so that the changes in deposition efficiency of the radioactive indoor aerosol with hygroscopic growth in the respiratory tract can be assessed.

  7. Study of the atmospheric chemistry of radon progeny in laboratory and real indoor atmospheres. Progress report, July 1, 1992--March 31, 1993

    SciTech Connect

    Hopke, P.K.

    1992-07-01

    This report describes studies on the chemical and physical behavior of the {sup 218}Po atom immediately following its formation by the alpha decay of radon. Because small changes in size for activity in the sub-10 nm size range result in large changes in the delivered dose per unit exposure, this behavior must be understood if the exposure to radon progeny and its dose to the cells in the respiratory tract are to be fully assessed. The specific tasks of the controlled laboratory studies are to determine the formation rates of {center_dot}OH radicals formed by the radiolysis of air following radon decay, to examine the formation of particles by the radiolytic oxidation of substances like SO{sub 2} ethylene, and H{sub 2}S to lower vapor pressure compounds and determine the role of gas phase additives such as H{sub 2}O and NH{sub 3} in determining the particle size, to measure the rate of ion-induced nucleation using a thermal diffusion cloud chamber, and to measure the neutralization rate of {sup 218}Po{sub x}{sup +} in O{sub 2} at low radon concentrations. Tasks of the exposure studies in occupied indoor spaces are to initiate measurements of the activity size distributions in actual homes with occupants present so that the variability of the indoor activity size distributions can be assessed with respect to indoor aerosol sources and general lifestyle variations of the occupants, to initiate a prospective study of the utility of measurement of deposited {sup 210}Pb embedded in glass surfaces as a measure of the long-term, integrated exposure of the population to radon, and to develop the methodology to determine the hygroscopicity of the indoor aerosol so that the changes in deposition efficiency of the radioactive indoor aerosol with hygroscopic growth in the respiratory tract can be assessed.

  8. Study of the atmospheric chemistry of radon progeny in laboratory and real indoor atmospheres. Progress report, May 1, 1993--January 31, 1994

    SciTech Connect

    Hopke, P.K.

    1993-01-01

    Progress is reported on the chemical and physical behavior of the {sup 218}Po atom immediately following its formation by the alpha decay of radon. Two areas of radon progeny behavior are being pursued; laboratory studies under controlled conditions to better understand the fundamental physical and chemical processes that affect the progeny`s atmospheric behavior and studies in actual indoor environments to develop a better assessment of the exposure of the occupants of that space to the size and concentration of the indoor radioactive aerosol. The specific tasks addressed were to determine the formation rates of {center_dot}OH radicals formed by the radiolysis of air following radon decay, to examine the formation of particles by the radiolytic oxidation of substances like SO{sub 2}, ethylene, and H{sub 2}S to lower vapor pressure compounds and determine the role of gas phase additives such as H{sub 2}O and NH{sub 3} in determining the particle size, to measure the rate of ion-induced nucleation using a thermal diffusion cloud chamber, and to measure the neutralization rate of {sup 218}PoO{sub x}{sup +} in O{sub 2} at low radon concentrations. Initial measurements were conducted of the activity size distributions in actual homes with occupants present so that the variability of the indoor activity size distributions can be assessed with respect to indoor aerosol sources and general lifestyle variations of the occupants. A prospective study of the utility of measurement of deposited {sup 210}Pb embedded in glass surfaces as a measure of the long-term, integrated exposure of the population to radon are described. Methodology was developed to determine the hygroscopicity of the indoor aerosol so that the changes in deposition efficiency of the radioactive indoor aerosol with hygroscopic growth in the respiratory tract can be assessed.

  9. Background modeling for the GERDA experiment

    NASA Astrophysics Data System (ADS)

    Becerici-Schmidt, N.; Gerda Collaboration

    2013-08-01

    The neutrinoless double beta (0νββ) decay experiment GERDA at the LNGS of INFN has started physics data taking in November 2011. This paper presents an analysis aimed at understanding and modeling the observed background energy spectrum, which plays an essential role in searches for a rare signal like 0νββ decay. A very promising preliminary model has been obtained, with the systematic uncertainties still under study. Important information can be deduced from the model such as the expected background and its decomposition in the signal region. According to the model the main background contributions around Qββ come from 214Bi, 228Th, 42K, 60Co and α emitting isotopes in the 226Ra decay chain, with a fraction depending on the assumed source positions.

  10. Quest for the lowest-energy neutrinos in Super-Kamiokande

    NASA Astrophysics Data System (ADS)

    Sekiya, Hiroyuki

    2015-08-01

    Super-Kamiokande (SK) has been observing 8B solar neutrinos for 17 years. Since the start of the SK-III phase, much effort has been expended in reducing backgrounds. The main contributing background comes from the beta decay of 214Bi, which is produced in the decays of radon in the purified air, detector materials, and the purified water. To reduce this background, the water system of SK has been upgraded. Heat exchangers for the cooling supply water were improved so as to suppress convection in the tank that transports radon near the photomultiplier tubes into the fiducial volume. To evaluate the remaining radon concentration, very-low-background radon detectors for air and water were designed and developed. Not only radon, but other contaminants in the water (bacteria and metal ions) were also investigated.

  11. Isotopic composition analysis and age dating of uranium samples by high resolution gamma ray spectrometry

    NASA Astrophysics Data System (ADS)

    Apostol, A. I.; Pantelica, A.; Sima, O.; Fugaru, V.

    2016-09-01

    Non-destructive methods were applied to determine the isotopic composition and the time elapsed since last chemical purification of nine uranium samples. The applied methods are based on measuring gamma and X radiations of uranium samples by high resolution low energy gamma spectrometric system with planar high purity germanium detector and low background gamma spectrometric system with coaxial high purity germanium detector. The "Multigroup γ-ray Analysis Method for Uranium" (MGAU) code was used for the precise determination of samples' isotopic composition. The age of the samples was determined from the isotopic ratio 214Bi/234U. This ratio was calculated from the analyzed spectra of each uranium sample, using relative detection efficiency. Special attention is paid to the coincidence summing corrections that have to be taken into account when performing this type of analysis. In addition, an alternative approach for the age determination using full energy peak efficiencies obtained by Monte Carlo simulations with the GESPECOR code is described.

  12. Quest for the lowest-energy neutrinos in Super-Kamiokande

    SciTech Connect

    Sekiya, Hiroyuki

    2015-08-17

    Super-Kamiokande (SK) has been observing {sup 8}B solar neutrinos for 17 years. Since the start of the SK-III phase, much effort has been expended in reducing backgrounds. The main contributing background comes from the beta decay of {sup 214}Bi, which is produced in the decays of radon in the purified air, detector materials, and the purified water. To reduce this background, the water system of SK has been upgraded. Heat exchangers for the cooling supply water were improved so as to suppress convection in the tank that transports radon near the photomultiplier tubes into the fiducial volume. To evaluate the remaining radon concentration, very-low-background radon detectors for air and water were designed and developed. Not only radon, but other contaminants in the water (bacteria and metal ions) were also investigated.

  13. Monitoring natural and artificial radioactivity enhancement in the Aegean Sea using floating measuring systems.

    PubMed

    Tsabaris, C

    2008-11-01

    In the present work, the enhancement of radioactivity due to rainfall in the Aegean Sea using floating measuring systems was observed and quantified. The data were acquired with a NaI underwater detection system, which was installed on a floating measuring system at a depth of 3m. The results of natural and artificial radioactivity are discussed taking into account the rainfall intensity and wind direction. The activity concentration of (214)Bi increased up to (991+/-102)Bq/m(3) after strong rainfall in the North Aegean Sea in winter (humid period) with east wind direction. On other hand, the maximum activity concentration reached the level of (110+/-10)Bq/m(3) in summer (dry period) during south winds. PMID:18495486

  14. Age-dating of highly enriched Uranium by γ-spectrometry

    NASA Astrophysics Data System (ADS)

    Tam Nguyen, Cong

    2005-02-01

    A non-destructive, γ-spectrometric method for uranium age-dating is reported for the first time. The method relies on measuring the daughter/parent activity ratio 214Bi/ 234U by low-background, high-resolution γ-spectrometry and does not require the use of reference samples of known ages. The initial methodology was derived during a "Round-Robin" exercise, in which the properties of a HEU material relevant to nuclear forensics were assessed by several laboratories. The Uranium-age obtained by this γ-spectrometric method is in agreement with the results reported by other participating laboratories, which used mass-spectrometry for age dating.

  15. Experimental set-up and optimization of a gamma-ray spectrometer for measurement of cosmogenic radionuclides in meteorites

    NASA Astrophysics Data System (ADS)

    Taricco, C.; Bhandari, N.; Colombetti, P.; Verma, N.; Vivaldo, G.

    2007-03-01

    We have developed a highly efficient and selective gamma-ray spectrometer with extremely low background for activity measurement of gamma emitting cosmogenic radionuclides in meteorites. This spectrometer can operate in specific modes to match decay scheme of a particular radionuclide and is specially suited for measurement of positron emitters. The system consists of a hyperpure Ge detector (3 kg, 147% relative efficiency), operating in coincidence with an umbrella of NaI(Tl) scintillator (90 kg) in order to achieve low background. The system is tuned such that strong interference due to naturally occurring uranium daughters, e.g. 214Bi present in the meteorites and in the laboratory environment, is minimized. It enables us to measure 44Ti (T=59.2y) which is ideal for studying centennial scale variations of cosmic ray flux in the interplanetary space with good reliability. The specific configuration of the coincidence system and electronics are described here.

  16. Natural radioactivity concentration of peanuts in Osmaniye-Turkey

    SciTech Connect

    Akkurt, Iskender; Guenoglu, Kadir; Mavi, Betuel; Kara, Ayhan

    2012-09-06

    The peanut is grown in Osmaniye where located in southern Turkey. Due to it is grown underground, the measurements of natural radioactivity of peanuts become important. For this reason some peanut samples have been collected from different places of Osmaniye and the measurements of natural activity concentrations for {sup 40}K, {sup 226}Ra and {sup 232}Th in some peanuts samples have been carried out using a NaI(Tl) gamma-ray spectrometer. Activity of {sup 40}K was measured from its intensive line at 1460 keV, for {sup 226}Ra activity peak from {sup 214}Bi at 1760 keV and {sup 232}Th activity, peak from {sup 208}Tl at energy of 2610 keV was used.

  17. Background modeling for the GERDA experiment

    SciTech Connect

    Becerici-Schmidt, N.; Collaboration: GERDA Collaboration

    2013-08-08

    The neutrinoless double beta (0νββ) decay experiment GERDA at the LNGS of INFN has started physics data taking in November 2011. This paper presents an analysis aimed at understanding and modeling the observed background energy spectrum, which plays an essential role in searches for a rare signal like 0νββ decay. A very promising preliminary model has been obtained, with the systematic uncertainties still under study. Important information can be deduced from the model such as the expected background and its decomposition in the signal region. According to the model the main background contributions around Q{sub ββ} come from {sup 214}Bi, {sup 228}Th, {sup 42}K, {sup 60}Co and α emitting isotopes in the {sup 226}Ra decay chain, with a fraction depending on the assumed source positions.

  18. Lifetimes of (214)Po and (212)Po measured with Counting Test Facility at Gran Sasso National Laboratory.

    PubMed

    Miramonti, L; Bellini, G; Benziger, J; Bick, D; Bonfini, G; Bravo, D; Buizza Avanzini, M; Caccianiga, B; Cadonati, L; Calaprice, F; Carraro, C; Cavalcante, P; Chavarria, A; Chubakov, V; D'Angelo, D; Davini, S; Derbin, A; Etenko, A; Fomenko, K; Franco, D; Galbiati, C; Gazzana, S; Ghiano, C; Giammarchi, M; Göger-Neff, M; Goretti, A; Grandi, L; Guardincerri, E; Hardy, S; Ianni, Aldo; Ianni, Andrea; Kobychev, V; Korablev, D; Korga, G; Koshio, Y; Kryn, D; Laubenstein, M; Lewke, T; Lissia, M; Litvinovich, E; Loer, B; Lombardi, F; Lombardi, P; Ludhova, L; Machulin, I; Manecki, S; Maneschg, W; Mantovani, F; Manuzio, G; Meindl, Q; Meroni, E; Misiaszek, M; Montanari, D; Mosteiro, P; Muratova, V; Nisi, S; Oberauer, L; Obolensky, M; Ortica, F; Otis, K; Pallavicini, M; Papp, L; Perasso, L; Perasso, S; Pocar, A; Ranucci, G; Razeto, A; Re, A; Romani, A; Rossi, N; Sabelnikov, A; Saldanha, R; Salvo, C; Schönert, S; Simgen, H; Skorokhvatov, M; Smirnov, O; Sotnikov, A; Sukhotin, S; Suvorov, Y; Tartaglia, R; Testera, G; Vignaud, D; Vogelaar, R B; von Feilitzsch, F; Winter, J; Wojcik, M; Wright, A; Wurm, M; Xhixha, G; Xu, J; Zaimidoroga, O; Zavatarelli, S; Zuzel, G

    2014-12-01

    The decays of (214)Po into (210)Pb and of (212)Po into (208)Pb tagged by the previous decays from (214)Bi and (212)Bi have been studied inserting quartz vials inside the Counting Test Facility (CTF) at the underground laboratory in Gran Sasso (LNGS). We find that the mean lifetime of (214)Po is (236.00 ± 0.42(stat) ± 0.15(syst)) μs and that of (212)Po is (425.1 ± 0.9(stat) ± 1.2(syst)) ns. Our results are compatible with previous measurements, have a much better signal to background ratio, and reduce the overall uncertainties. PMID:24725806

  19. The BiPo detector for ultralow radioactivity measurements

    SciTech Connect

    Bongrand, M.

    2007-03-28

    The BiPo project is dedicated to the measurement of extremely low radioactivity contamination of SuperNEMO source foils (208Tl < 2 {mu}Bq/kg and 214Bi < 10 {mu}Bq/kg). The R and D phase is started : a modular BiPo prototype with its shielding test facility is under construction. The goal of this prototype is to study the background and particularly the surface contamination of scintillators. The first capsule has been installed in the Canfranc Underground Laboratory in October, 17th and is now taking data. After 10.7 days of measurements, a preliminary upper limit on the surface radiopurity of the scintillators of A(208Tl) < 60 {mu}Bq/m2 (90% C. L.) has been obtained.

  20. Apparatus development for measurement of (134)Cs and (137)Cs radioactivity of soil contaminated by the Fukushima Daiichi Nuclear Power Plant accident.

    PubMed

    Kajimoto, Tsuyoshi; Endo, Satoru; Tanaka, Kenichi; Okashiro, Yasuharu; Kai, Hiroaki; Fujii, Syuuji; Mishima, Atsushi; Matsubara, Takahide; Yoshida, Shinji

    2016-09-01

    We developed an apparatus containing a NaI(Tl) scintillator to measure the (134)Cs and (137)Cs radioactivity of soil contaminated by the Fukushima Daiichi Nuclear Power Plant accident. The unfolding method with the least-squares technique was used to determine the radioactivity. Detector responses for each radionuclide in soil were calculated with EGS5 code for the unfolding method. The radionuclides that were measured were (40)K, (134)Cs, (137)Cs, (208)Tl, (214)Bi, and (228)Ac. The measured spectrum agreed well with the spectrum calculated from the response matrix and measured radioactivities. The unfolding method allows us to use the NaI(Tl) scintillator despite the overlap of peaks. PMID:27289189

  1. An aerial radiological survey of the Davis-Monthan Air Force Base and surrounding area, Tucson, Arizona

    SciTech Connect

    1995-09-01

    An aerial radiological survey, which was conducted from March 1 to 13, 1995, covered a 51-square-mile (132-square-kilometer) area centered on the Davis-Monthan Air Force Base (DMAFB) in Tucson, Arizona. The results of the survey are reported as contours of bismuth-214 ({sup 214}Bi) soil concentrations, which are characteristic of natural uranium and its progeny, and as contours of the total terrestrial exposure rates extrapolated to one meter above ground level. All data were scaled and overlaid on an aerial photograph of the DMAFB area. The terrestrial exposure rates varied from 9 to 20 microroentgens per hour at one meter above the ground. Elevated levels of terrestrial radiation due to increased concentrations of {sup 214}Bi (natural uranium) were observed over the Southern Pacific railroad yard and along portions of the railroad track bed areas residing both within and outside the base boundaries. No man-made, gamma ray-emitting radioactive material was observed by the aerial survey. High-purity germanium spectrometer and pressurized ionization chamber measurements at eight locations within the base boundaries were used to verify the integrity of the aerial results. The results of the aerial and ground-based measurements were found to be in agreement. However, the ground-based measurements were able to detect minute quantities of cesium-137 ({sup 137}Cs) at six of the eight locations examined. The presence of {sup 137}Cs is a remnant of fallout from foreign and domestic atmospheric nuclear weapons testing that occurred in the 1950s and early 1960s. Cesium-137 concentrations varied from 0.1 to 0.3 picocuries per gram, which is below the minimum detectable activity of the aerial system.

  2. Measurement of 224Ra and 226Ra activities in natural waters using a radon-in-air monitor

    USGS Publications Warehouse

    Kim, G.; Burnett, W.C.; Dulaiova, H.; Swarzenski, P.W.; Moore, W.S.

    2001-01-01

    We report a simple new technique for measuring low-level radium isotopes (224Ra and 226Ra) in natural waters. The radium present in natural waters is first preconcentrated onto MnO2-coated acrylic fiber (Mn fiber) in a column mode. The radon produced from the adsorbed radium is then circulated through a closed air-loop connected to a commercial radon-in-air monitor. The monitor counts alpha decays of radon daughters (polonium isotopes) which are electrostatically collected onto a silicon semiconductor detector. Count data are collected in energy-specific windows, which eliminate interference and maintain very low backgrounds. Radium-224 is measured immediately after sampling via 220Rn (216Po), and 226Ra is measured via 222Rn (218Po) after a few days of ingrowth of 222Rn. This technique is rapid, simple, and accurate for measurements of low-level 224Ra and 226Ra activities without requiring any wet chemistry. Rapid measurements of short-lived 222Rn and 224Ra, along with long-lived 226Ra, may thus be made in natural waters using a single portable system for environmental monitoring of radioactivity as well as tracing of various geochemical and geophysical processes. The technique could be especially useful for the on-site rapid determination of 224Ra which has recently been found to occur at elevated activities in some groundwater wells.

  3. Measurement of α -particle quenching in LAB based scintillator in independent small-scale experiments

    NASA Astrophysics Data System (ADS)

    von Krosigk, B.; Chen, M.; Hans, S.; Junghans, A. R.; Kögler, T.; Kraus, C.; Kuckert, L.; Liu, X.; Nolte, R.; O'Keeffe, H. M.; Tseung, H. Wan Chan; Wilson, J. R.; Wright, A.; Yeh, M.; Zuber, K.

    2016-03-01

    The α -particle light response of liquid scintillators based on linear alkylbenzene (LAB) has been measured with three different experimental approaches. In the first approach, α -particles were produced in the scintillator via ^{12}C( n,α )^9Be reactions. In the second approach, the scintillator was loaded with 2 % of ^{nat}Sm providing an α -emitter, ^{147}Sm, as an internal source. In the third approach, a scintillator flask was deployed into the water-filled SNO+ detector and the radioactive contaminants ^{222}Rn, ^{218}Po and ^{214}Po provided the α -particle signal. The behavior of the observed α -particle light outputs are in agreement with each case successfully described by Birks' law. The resulting Birks parameter kB ranges from (0.0066± 0.0016) to (0.0076± 0.0003) cm/MeV. In the first approach, the α -particle light response was measured simultaneously with the light response of recoil protons produced via neutron-proton elastic scattering. This enabled a first time a direct comparison of kB describing the proton and the α -particle response of LAB based scintillator. The observed kB values describing the two light response functions deviate by more than 5σ . The presented results are valuable for all current and future detectors, using LAB based scintillator as target, since they depend on an accurate knowledge of the scintillator response to different particles.

  4. A novel approach for long-term determination of indoor 222Rn progeny equilibrium factor using nuclear track detectors

    NASA Astrophysics Data System (ADS)

    Amgarou, K.; Font, Ll.; Baixeras, C.

    2003-06-01

    A detailed study of the measurement principles of airborne 222Rn decay products by means of nuclear track detectors (NTDs), taking into account the range of variation of the parameters influencing their concentration indoors, has shown that it is not possible for the existing methods to obtain the associated long-term equilibrium factor with an appropriate accuracy. For this reason, we have established a novel approach based on the new concept of reduced equilibrium factor, which can be obtained from the only measurement of airborne 222Rn and its α-emitter daughter ( 218Po and 214Po) concentrations using a passive, integrating and multi-component system of NTDs. We have found that the equilibrium factor has a linear dependence on the reduced equilibrium factor regardless the values taken for the rates of ventilation, of aerosol attachment and of surface deposition. By using well-controlled exposures in a reference laboratory, we have shown that the equilibrium factor values determined with our system agree with those obtained by active monitors. Finally, as a pilot test, several dosimeters were exposed in an inhabited Swedish single-family house. The results of this exposure suggest the usefulness of this method to perform routine surveys in private homes and in workplaces in order to estimate the annual effective dose received by the general public and the workers due to the presence of 222Rn daughters.

  5. Activity concentrations of 222Rn, 220Rn, and their decay products in german dwellings, dose calculations and estimate of risk.

    PubMed

    Keller, G; Folkerts, K H; Muth, H

    1982-01-01

    Measurements of the concentrations of 222Rn, its short-lived decay products and of 212Pb - 212Bi were performed in 150 dwellings and in the open air in the Federal Republic of Germany. The concentrations of 222Rn was measured by electrostatic deposition of 218Po. The concentration of the short-lived decay products were measured by air sampling and alpha-spectroscopy. It was found that inside dwellings the average potential alpha-energy concentration of the short-lived daughters is about three times higher than in the open air. The total potential alpha-energy concentration indoors amounts to 2.6 . 10(-3) Working Level (W.L.). Direct measurements of the equilibrium factor inside dwellings gave a mean value of 0.3. A strong dependence of the potential alpha energy concentration on the ventilation rate in dwellings has been observed. These ventilation effects exceed the effects caused by differences in the activity concentrations due to different building materials. The dose calculation results in an average dose to the whole lung due to the inhalation of short-lived radon daughters of about 0.05-0.2 m/Gy/a. An estimate of risk - based on the risk factors for uranium miners - shows an average lifetime risk of about 6 . 10(-4) for the incidence of lung cancer caused by inhalation of radon and thoron daughters in dwellings in the Federal Republic of Germany. PMID:7146318

  6. Neutralization of thoron progeny in gases.

    PubMed

    Cheng, Y S; Yu, C C; Tung, C J; Hopke, P K

    1994-08-01

    This paper reports charge neutralization phenomena of 212Pb particles in nitrogen or oxygen atmospheres with trace amounts of other gases. Newly produced thoron or radon progeny are positively charged, stable molecular clusters that are subsequently neutralized by several mechanisms. The charged clusters have a smaller diffusion coefficient than neutral clusters of the same size due to the interaction of the charge with the surrounding gas molecules. In this study, we have found that the diffusion coefficients of 212Pb in O2, N2, NH3/O2, NH3/N2, and C6H12/N2 (IPs between 15.58 and 9.8 eV) ranged between 0.015 and 0.030 cm2 s-1. In the case of C6H12/O2, NO2/O2, NO/O2, and dimethylamine/O2 (ionization potential between 9.8 and 8.23 eV), the diffusion coefficients have increased to between 0.046 and 0.69 cm2 s-1. These results are consistent with previous results of 218Po, indicating that charged progeny are neutralized by electron transfer from a gas molecule with a lower ionization potential than lead oxide. We estimate the ionization potential of lead oxide to range between 9.8 and 10.2 eV. 212Pb was also neutralized by an electron scavenging mechanism in NO2/nitrogen. PMID:8026969

  7. Metrological Determination of Natural Radioactive Isotopes {sup 226}Ra, {sup 228}Ra and {sup 210}Pb by Means of Ge Detector

    SciTech Connect

    Almeida, Maria Candida M. de; Delgado, Jose U.; Poledna, Roberto; Oliveira, Estela Maria de; Silva, Ronaldo L. da

    2008-08-07

    A metrological method to determine the activity per mass unity (activity concentration) of {sup 226}Ra and {sup 210}Pb ({sup 238}U decay series) and {sup 228}Ra ({sup 232}Th series) by gamma-ray spectrometers based on hyper-pure coaxial germanium detector was developed. In the soil the {sup 22}Ra (half-life = 1600 years) exhibits the same level of radioactivity as {sup 238}U (half-life 4.5x10{sup 9} years) because of a natural phenomenon called secular equilibrium. {sup 226}Ra decays into {sup 222}Rn (half-life = 3.8 days), a radioactive inert gas. After several days, the {sup 222}Rn naturally decays to {sup 218}Po (half-life = 3 minutes), where finally {sup 210}Pb (half-life = 22 years) is produced. The metrological capability of high-resolution gamma-ray spectrometry for naturally occurring radionuclides at environmental levels is showed, with emphasis on the use of 2 mL standard sources volume in a glass ampoule. Source preparation and calibration procedures are described. Radionuclide standards in an activity range of 10 to 250 Bq/g were produced which can be applied in a variety of environmental sample analysis (water, plant material, sediment, etc.). Uncertainties for {sup 226}Ra and {sup 210}Pb around 3% (k = 1) were obtained.

  8. RADON AND PROGENY ALPHA-PARTICLE ENERGY ANALYSIS USING NUCLEAR TRACK METHODOLOGY

    SciTech Connect

    Espinosa Garcia, Guillermo; Golzarri y Moreno, Dr. Jose Ignacio; Bogard, James S

    2008-01-01

    A preliminary procedure for alpha energy analysis of radon and progeny using Nuclear Track Methodology (NTM) is described in this paper. The method is based on the relationship between alpha-particle energies deposited in polycarbonate material (CR-39) and the track size developed after a well-established chemical etching process. Track geometry, defined by parameters such as major or minor diameters, track area and overall track length, is shown to correlate with alpha-particle energy over the range 6.00 MeV (218Po) to 7.69 MeV (214Po). Track features are measured and the data analyzed automatically using a digital imaging system and commercial PC software. Examination of particle track diameters in CR-39 exposed to environmental radon reveals a multi-modal distribution. Locations of the maxima in this distribution are highly correlated with alpha particle energies of radon daughters, and the distributions are sufficiently resolved to identify the radioisotopes. This method can be useful for estimating the radiation dose from indoor exposure to radon and its progeny.

  9. The detection and measurement of the electrical mobility size distributions associated with radon decay products

    SciTech Connect

    Fei, Lin

    1996-04-01

    The potential risk of lung cancer has evoked interest in the properties of radon decay products. There are two forms of this progeny: either attached to ambient aerosols, or still in the status of ions/molecules/small clusters. This ``unattached`` activity would give a higher dose per unit of airborne activity than the ``attached`` progeny that are rather poorly deposited. In this thesis, a system for determining unattached radon decay products electrical mobility size distribution by measuring their electrical mobilities was developed, based on the fact that about 88% of {sup 218}Po atoms have unit charge at the end of their recoil after decay from {sup 222}Rn, while the remainder are neutral. Essential part of the setup is the radon-aerosol chamber with the Circular Electrical Mobility Spectrometer (CEMS) inside. CEMS is used for sampling and classifying the charged radioactive clusters produced in the chamber. An alpha- sensitive plastic, CR-39 disk, is placed in CEMS as an inlaid disk electrode and the alpha particle detector. CEMS showed good performance in fine inactive particles` classification. If it also works well for radon decay products, it can offer a convenient size distribution measurement for radioactive ultrafine particles. However, the experiments did not obtain an acceptable resolution. Suggestions are made for solving this problem.

  10. Clean galena, contaminated lead, and soft errors in memory chips

    NASA Astrophysics Data System (ADS)

    Lykken, G. I.; Hustoft, J.; Ziegler, B.; Momcilovic, B.

    2000-10-01

    Lead (Pb) disks were exposed to a radon (Rn)-rich atmosphere and surface alpha particle emissions were detected over time. Cumulative 210Po alpha emission increased nearly linearly with time. Conversely, cumulative emission for each of 218Po and 214Po was constant after one and two hours, respectively. Processing of radiation-free Pb ore (galena) in inert atmospheres was compared with processing in ambient air. Galena processed within a flux heated in a graphite crucible while exposed to an inert atmosphere, resulted in lead contaminated with 210Po (Trial 1). A glove box was next used to prepare a baseline radiation-free flux sample in an alumina crucible that was heated in an oven with an inert atmosphere (Trials 2 and 3). Ambient air was thereafter introduced, in place of the inert atmosphere, to the radiation-free flux mixture during processing (Trial 4). Ambient air introduced Rn and its progeny (RAD) into the flux during processing so that the processed Pb contained Po isotopes. A typical coke used in lead smelting also emitted numerous alpha particles. We postulate that alpha particles from tin/lead solder bumps, a cause of computer chip memory soft errors, may originate from Rn and RAD in the ambient air and/or coke used as a reducing agent in the standard galena smelting procedure.

  11. Nuclear Data Sheets for A = 218

    SciTech Connect

    Jain, Ashok K.; Singh, Balraj

    2006-04-15

    Nuclear spectroscopic information for known nuclides of mass number 218 (Bi,Po,At,Rn,Fr,Ra,Ac,Th,Pa,U) with Z = 83 to 92 and N = 135 to 126 have been evaluated and presented together with adopted energies and J{pi} of levels in these nuclei. No excited state data are yet available for {sup 218}Bi, {sup 218}At and {sup 218}Pa. Octupole structures are known in {sup 218}Rn, {sup 218}Fr, {sup 218}Ra and {sup 218}Ac nuclides. Since the previous update (1995El08) about ten years ago, many new data are available e.g. decays of {sup 218}Bi to {sup 218}Po, {sup 222}Ra to {sup 218}Rn and {sup 222}Th to {sup 218}Ra; high-spin structures in {sup 218}Rn and {sup 218}Fr; and lifetimes of excited states in {sup 218}Ra. This evaluation supersedes previous full evaluations of A = 218 published by 1987El12 and 1977To13; and an interim evaluation published in 'update' mode by 1995El08 with literature cutoff date of August 1995.

  12. Radon in the DRIFT-II directional dark matter TPC: emanation, detection and mitigation

    NASA Astrophysics Data System (ADS)

    Battat, J. B. R.; Brack, J.; Daw, E.; Dorofeev, A.; Ezeribe, A. C.; Fox, J. R.; Gauvreau, J.-L.; Gold, M.; Harmon, L. J.; Harton, J. L.; Landers, J. M.; Lee, E. R.; Loomba, D.; Matthews, J. A. J.; Miller, E. H.; Monte, A.; Murphy, A. StJ.; Paling, S. M.; Phan, N.; Pipe, M.; Robinson, M.; Sadler, S. W.; Scarff, A.; Snowden-Ifft, D. P.; Spooner, N. J. C.; Telfer, S.; Walker, D.; Warner, D.; Yuriev, L.

    2014-11-01

    Radon gas emanating from materials is of interest in environmental science and also a major concern in rare event non-accelerator particle physics experiments such as dark matter and double beta decay searches, where it is a major source of background. Notable for dark matter experiments is the production of radon progeny recoils (RPRs), the low energy (~ 100 keV) recoils of radon daughter isotopes, which can mimic the signal expected from WIMP interactions. Presented here are results of measurements of radon emanation from detector materials in the 1 m3 DRIFT-II directional dark matter gas time projection chamber experiment. Construction and operation of a radon emanation facility for this work is described, along with an analysis to continuously monitor DRIFT data for the presence of internal 222Rn and 218Po. Applying this analysis to historical DRIFT data, we show how systematic substitution of detector materials for alternatives, selected by this device for low radon emanation, has resulted in a factor of ~ 10 reduction in internal radon rates. Levels are found to be consistent with the sum from separate radon emanation measurements of the internal materials and also with direct measurement using an attached alpha spectrometer. The current DRIFT detector, DRIFT-IId, is found to have sensitivity to 222Rn of 2.5 μBql-1 with current analysis efficiency, potentially opening up DRIFT technology as a new tool for sensitive radon assay of materials.

  13. Equilibration correction of temporal measurements for sudden 222Rn concentration changes

    NASA Astrophysics Data System (ADS)

    Tan, Y.; Tokonami, S.; Liu, H.; Kearfott, K. J.

    2016-02-01

    222Rn and 220Rn can be used as tracers of groundwater or submarine springs, and 222Rn in water also could indicate indoor radon problems in some regions. The half-life of 222Rn is long enough that its concentration may remain significant during transit over relatively long distances, while that of 220Rn is not. Prior research revealed that it took about 15 min for the radon to achieve gas equilibrium at a water flow rate of 17.5 L min-1, which is approximately equivalent to the time required for the 222Rn-218Po pair to approach radioactive equilibrium and is limiting in terms of measurements of sudden radon concentration change. In this work, an algorithm is applied to improve the continuous tracing of radon concentrations in the field environment. Results of a laboratory experiment analyzed applying the analysis method illustrated its ability to allow immediate identification of sharp concentration increases. In this paper we find that a precipitous drop in radon concentrations lead to improper corrected values as the result of measurement uncertainties prior to the drop, and a method using zero instead negative values for reducing the uncertainties under such condition also is proposed.

  14. Network of seismo-geochemical monitoring observatories for earthquake prediction research in India

    NASA Astrophysics Data System (ADS)

    Chaudhuri, Hirok; Barman, Chiranjib; Iyengar, A.; Ghose, Debasis; Sen, Prasanta; Sinha, Bikash

    2013-08-01

    Present paper deals with a brief review of the research carried out to develop multi-parametric gas-geochemical monitoring facilities dedicated to earthquake prediction research in India by installing a network of seismo-geochemical monitoring observatories at different regions of the country. In an attempt to detect earthquake precursors, the concentrations of helium, argon, nitrogen, methane, radon-222 (222Rn), polonium-218 (218Po), and polonium-214 (214Po) emanating from hydrothermal systems are monitored continuously and round the clock at these observatories. In this paper, we make a cross correlation study of a number of geochemical anomalies recorded at these observatories. With the data received from each of the above observatories we attempt to make a time series analysis to relate magnitude and epicentral distance locations through statistical methods, empirical formulations that relate the area of influence to earthquake scale. Application of the linear and nonlinear statistical techniques in the recorded geochemical data sets reveal a clear signature of long-range correlation in the data sets.

  15. Bioaccessibility of U, Th and Pb in particulate matter from an abandoned uranium mine

    NASA Astrophysics Data System (ADS)

    Millward, Geoffrey; Foulkes, Michael; Henderson, Sam; Blake, William

    2016-04-01

    Currently, there are approximately 150 uranium mines in Europe at various stages of either operation, development, decommissioning, restoration or abandonment (wise-uranium.com). The particulate matter comprising the mounds of waste rock and mill tailings poses a risk to human health through the inadvertent ingestion of particles contaminated with uranium and thorium, and their decay products, which exposes recipients to the dual toxicity of heavy elements and their radioactive emissions. We investigated the bioaccessibility of 238U, 232Th and 206,214,210Pb in particulate samples taken from a contaminated, abandoned uranium mine in South West England. Sampling included a mine shaft, dressing floor and waste heap, as well as soils from a field used for grazing. The contaminants were extracted using the in-vitro Unified Bioaccessibility Research Group of Europe Method (UBM) in order to mimic the digestion processes in the human stomach (STOM) and the combined stomach and gastrointestinal tract (STOM+INT). Analyses of concentrations of U, Th and Pb in the extracts were by ICP-MS and the activity concentrations of radionuclides were determined on the same particles, before and after extraction, using gamma spectroscopy. 'Total' concentrations of U, Th and Pb for all samples were in the range 57 to 16,200, 0.28 to 3.8 and 69 to 4750 mg kg‑1, respectively. For U and Pb the concentrations in the STOM fraction were lower than the total and STOM+INT fractions were even lower. However, for Th the STOM+INT fractions were higher than the STOM due to the presence of Th carbonate species within the gastrointestinal fluid. Activity concentrations for 214Pb and 210Pb, including total, STOM and STOM+INT, were in the range 180 to <1 Bq g‑1 for the dressing floor and waste heap and 18 to <1 Bq g‑1 for the grazing land. Estimates of the bioaccessible fractions (BAFs) of 238U in the most contaminated samples were 39% and 8% in the STOM and STOM+INT, respectively, whereas the

  16. A radiometric and petrographic interpretation of discrepancies on uranium content in samples collected at Alte Madonie Mounts region (Sicily, Italy).

    PubMed

    Lanzo, G; Rizzo, S; Tomarchio, E

    2014-03-01

    The main goal of this work is to evaluate a correlation between anomalous Uranium (U) content and petrographic features of some soil and rock samples collected at Alte Madonie Mounts region (North-central Sicily, Italy). A total of 41 samples of selected soils and rocks were collected, powdered, dried and sealed in "Marinelli" beakers for 20 days before the measurement to ensure that radioactive equilibrium between (226)Ra and (214)Bi was reached. Gamma-ray spectrometric analysis was used to quantify radioactivity concentrations. Mineralogical and chemical features of the samples were determined by X-ray Fluorescence (XRF), X-ray Diffractometry (XRD), Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) and Scanning Electron Microscope - Energy Dispersive Spectrometry (SEM-EDS) analyses. The average values of concentrations of (226)Ra, (228)Ac and (40)K were respectively 30, 17 and 227 Bq kg(-1) while the greatest values were 134, 59 and 748 Bq kg(-1). Linear relationships were observed between (226)Ra, (228)Ac and (40)K concentrations: the activities of (226)Ra and (228)Ac were comparable, while those of (40)K were about 10 times greater. An exception was highlighted for a group of samples where (226)Ra activities were much higher than expectations. Chemical compositions and mineralogical features of the samples have made it possible to justify these anomalies. PMID:24389108

  17. Discrimination between natural and other gamma ray sources from environmental gamma ray dose rate monitoring data.

    PubMed

    Kumagai, K; Ookubo, H; Kimura, H

    2015-11-01

    In this study, a method to discriminate between natural and other γ-ray sources from environmental γ-ray dose rate monitoring data was developed, and it was successfully applied to actual monitoring data around nuclear facilities. The environmental dose rate is generally monitored by NaI(Tl) detector systems in the low dose rate range. The background dose rate varies mainly as a result of the deposition of (222)Rn progeny in precipitation and shielding of the ground by snow cover. Increments in the environmental dose rate due to radionuclides released from nuclear facilities must be separated from these background variations. The method in the present study corrects for the dose rate variations from natural sources by multiple regression analysis based on the γ-ray counting rates of single-channel analysers opened in the energy ranges of γ-rays emitted by (214)Bi and (208)Tl. Assuming a normal distribution of the results and using the one-sided type I error of 0.01 while ignoring the type II error, the detection limit of the γ-ray dose rate from artificial sources was 0.77 nGy h(-1). PMID:25948830

  18. Low Radioactive Techniques in SuperNEMO: Status of the Radon R and D

    SciTech Connect

    Perrot, F.

    2011-04-27

    Radon is a well-known source of background with respect to the search for neutrinoless double beta decay (0{nu}{beta}{beta}), due to the high Q{sub {beta}} value of one of its daughter nucleus {sup 214}Bi. Radon has been observed and reduced down to 6.5 mBq/m{sup 3} in the NEMO-3 experiment which is looking for the 0{nu}{beta}{beta} process in {sup 100}Mo and in six other isotopes. The SuperNEMO project, a next-generation double beta decay experiment which will also use a tracko-calorimeter technique, has been in an R and D phase since 2006. The goal is to reach a sensitivity of T{sub 1/2}(0{nu})>10{sup 26} y corresponding to an effective Majorana neutrino mass of 0.05-0.1 eV with 100 kg of {sup 82}Se. Such a sensitivity requires in particular to improve the radon radiopurity down to 0.1 mBq/m{sup 3} in the tracking chamber.

  19. Radon emanation chamber: High sensitivity measurements for the SuperNEMO experiment

    SciTech Connect

    Soulé, B.; Collaboration: SuperNEMO Collaboration; and others

    2013-08-08

    Radon is a well-known source of background in ββ0ν experiments due to the high Q{sub β} value of one of its daughter nucleus, {sup 214}Bi. The SuperNEMO collaboration requires a maximum radon contamination of 0.1 mBq/m{sup 3} inside its next-generation double beta decay detector. To reach such a low activity, a drastic screening process has been set for the selection of the detector's materials. In addition to a good radiopurity, a low emanation rate is required. To test this parameter, a Radon Emanation Setup is running at CENBG. It consists in a large emanation chamber connected to an electrostatic detector. By measuring large samples and having a low background level, this setup reaches a sensitivity of a few μ Bq. m{sup −2}. d{sup −1} and is able to qualify materials used in the construction of the SuperNEMO detector.

  20. Results of the BiPo-1 prototype for radiopurity measurements for the SuperNEMO double beta decay source foils

    NASA Astrophysics Data System (ADS)

    Argyriades, J.; Arnold, R.; Augier, C.; Baker, J.; Barabash, A. S.; Basharina-Freshville, A.; Bongrand, M.; Bourgeois, C.; Breton, D.; Brière, M.; Broudin-Bay, G.; Brudanin, V. B.; Caffrey, A. J.; Carcel, S.; Cebrián, S.; Chapon, A.; Chauveau, E.; Dafni, Th.; Díaz, J.; Durand, D.; Egorov, V. G.; Evans, J. J.; Flack, R.; Fushima, K.-I.; Irastorza, I. G.; Garrido, X.; Gómez, H.; Guillon, B.; Holin, A.; Hommet, J.; Holy, K.; Horkey, J. J.; Hubert, P.; Hugon, C.; Iguaz, F. J.; Ishihara, N.; Jackson, C. M.; Jenzer, S.; Jullian, S.; Kauer, M.; Kochetov, O. I.; Konovalov, S. I.; Kovalenko, V.; Lamhamdi, T.; Lang, K.; Lemière, Y.; Lutter, G.; Luzón, G.; Mamedov, F.; Marquet, Ch.; Mauger, F.; Monrabal, F.; Nachab, A.; Nasteva, I.; Nemchenok, I. B.; Nguyen, C. H.; Nomachi, M.; Nova, F.; Ohsumi, H.; Pahlka, R. B.; Perrot, F.; Piquemal, F.; Povinec, P. P.; Richards, B.; Ricol, J. S.; Riddle, C. L.; Rodríguez, A.; Saakyan, R.; Sarazin, X.; Sedgbeer, J. K.; Serra, L.; Shitov, Yu. A.; Simard, L.; Šimkovic, F.; Söldner-Rembold, S.; Štekl, I.; Sutton, C. S.; Tamagawa, Y.; Szklarz, G.; Thomas, J.; Thompson, R.; Timkin, V.; Tretyak, V.; Tretyak, Vl. I.; Umatov, V. I.; Vála, L.; Vanyushin, I. A.; Vasiliev, R.; Vasiliev, V. A.; Vorobel, V.; Waters, D.; Yahlali, N.; Žukauskas, A.; SuperNEMO Collaboration

    2010-10-01

    The development of BiPo detectors is dedicated to the measurement of extremely high radiopurity in 208Tl and 214Bi for the SuperNEMO double beta decay source foils. A modular prototype, called BiPo-1, with 0.8 m2 of sensitive surface area, has been running in the Modane Underground Laboratory since February, 2008. The goal of BiPo-1 is to measure the different components of the background and in particular the surface radiopurity of the plastic scintillators that make up the detector. The first phase of data collection has been dedicated to the measurement of the radiopurity in 208Tl. After more than one year of background measurement, a surface activity of the scintillators of A(Tl208)=1.5 μBq/m2 is reported here. Given this level of background, a larger BiPo detector having 12 m2 of active surface area, is able to qualify the radiopurity of the SuperNEMO selenium double beta decay foils with the required sensitivity of A(Tl208)<2 μBq/kg (90% C.L.) with a six month measurement.

  1. Analytical evaluation of natural radionuclides and their radioactive equilibrium in raw materials and by-products.

    PubMed

    Ji, Young-Yong; Chung, Kun Ho; Lim, Jong-Myoung; Kim, Chang-Jong; Jang, Mee; Kang, Mun Ja; Park, Sang Tae

    2015-03-01

    An investigation into the distribution of natural radionuclides and radioactive secular equilibrium in raw materials and by-products in a domestic distribution was conducted to deduce the optimum conditions for the analytical evaluation of natural radionuclides for (238)U, (226)Ra, and (232)Th using a gamma-ray spectrometer and inductively coupled plasma mass spectrometer (ICP-MS). The range of the specific activities of natural radionuclides was first evaluated by analyzing (228)Ac and (214)Bi, which are (232)Th and (226)Ra indicators, respectively, in about 100 samples of raw materials and by-products through a gamma-ray spectrometer. From further experiments using several samples selected based on the results of the distribution of natural radionuclides, the validation of their analytical evaluations for the indirect measurements using a gamma-ray spectrometer and direct measurements using ICP-MS was assured by comparing their results. Chemically processed products from the raw materials, such as Zr sand and ceramic balls, were generally shown for the type of bead and particularly analyzed showing a definite disequilibrium with above a 50% difference between (238)U and (226)Ra in the uranium series and (232)Th and (228)Ra in the thorium series. PMID:25527894

  2. Evaluation of heat generation by radioactive decay of sedimentary rocks in Eastern Desert and Nile Valley, Egypt.

    PubMed

    Abbady, Adel G E

    2010-10-01

    Radioactive heat-production (RHP) data of sedimentary outcrops in Gebel Anz (Eastern Desert) and Gebel Sarai (Nile Valley) are presented. A total of 103 rock samples were investigated, covering all major rock types of the areas. RHP were derived from uranium, thorium and potassium concentrations measured from gamma-radiation originating from the decay of (214)Bi ((238)U series), (208)Tl ((232)Th series) and the primary decay of (40)K, obtained with a NaI (Tl) detector. The heat-production rate of Gebel Anz ranges from 0.94 (Nubai Sandstone ) to 5.22 microW m(-3) (Duwi Formation). In Gebel Sarai it varies from 0.82 (Esna Shale) to 7 microW m(-3) (Duwi Formation). The contribution due to U is about 62%, from Th is 34% and 4% from K in Gebel Anz. The corresponding values in Gebel Sarai are 69.6%, 26.9% and 3.5%, respectively. These data can be used to discuss the effects of the lateral variation of the RHP rate on the heat flux and the temperature fields in the upper crust. PMID:20472452

  3. Unusual 232Th and 238U contamination on some road surfaces in Taoyuan, Taiwan.

    PubMed

    Chang, W P; Nabyvanets, Y B; Jen, M H

    2001-06-01

    At least eight bustling streets or approximately 3-5% of all the road surface of civilian utility in the downtown area of Taoyuan City, Taiwan, were inadvertently found to contain unusual levels of radioactivity during a routine environmental radiation surveillance in mid-1994. Crushed rock debris and coarse sands separated from the asphalt pavement were identified to be the source of excessive radioactivity. By employing gamma spectrometry, we have measured 232Th activity (via 228Ac) and mU activity (via 214Bi) in some of the samples to be up to about 4,000 and 1,000 Bq kg(-1), respectively. The dose rate on the road surface reached about 1.3 microSv h(-1), as compared with the background level of 0.08 microSv h(-1) in much of Taiwan. This unusual radioactivity was due to accidental mixing of road construction materials with materials enriched 232Th and 238U. PMID:11388731

  4. [Determination of natural radioactive nuclides in the travertine samples from Tamagawa hot spring].

    PubMed

    Hashimoto, T; Masumura, S; Takahashi, K; Sotobayashi, T

    1982-07-01

    The determination of natural radioactive nuclides was carried out for 7 travertine samples collected from Tamagawa hot spring by means of the non-distructive gamma-ray spectrometry and of the alpha-ray spectrometry. From the former measurements, the relative activity strength, due to 223Ra, 226Ra, and 228Th, and their ratios was obtained in comparison with the photopeak strength due to respective daughters, 228Ac, 214Bi, and 212Pb, and with the results from a monazite sand standard. One travertine sample was engaged to the alpha-ray spectrometric determination of Th isotopes after the chemical purification using a 234Th-yield tracer. On the basis of the resultant absolute content of 228Th, the 228Ra and 228Th contents in the remainder samples were evaluated to be the range of 3 approximately 80 Bq (81 approximately 2160 pCi)/g and 2 approximately 20 Bq (54 approximately pCi)/g respectively. These radioactive nuclides were verified to exist almost within a Hokutolite small crystals up to 90% and there are apparently the radioactive disequilibrium relations between 228Ra and 228Th among freshly deposited travertines. The presence of 227Ac in Hokutolite was also suggested from the detection of 227Th owing to 215Po-alpha peak. PMID:7178540

  5. Low gamma counting for measuring NORM/TENORM with a radon reducing system

    NASA Astrophysics Data System (ADS)

    Paschoa, Anselmo S.

    2001-06-01

    A detection system for counting low levels of gamma radiation was built by upgrading an existing rectangular chamber made of 18 metric tonne of steel fabricated before World War II. The internal walls, the ceiling, and the floor of the chamber are covered with copper sheets. The new detection system consists of a stainless steel hollow cylinder with variable circular apertures in the cylindrical wall and in the base, to allow introduction of a NaI (Tl) crystal, or alternatively, a HPGe detector in its interior. This counting system is mounted inside the larger chamber, which in turn is located in a subsurface air-conditioned room. The access to the subsurface room is made from a larger entrance room through a tunnel plus a glass anteroom to decrease the air-exchange rate. Both sample and detector are housed inside the stainless steel cylinder. This cylinder is filled with hyper pure nitrogen gas, before counting a sample, to prevent radon coming into contact with the detector surface. As a consequence, the contribution of the 214Bi photopeaks to the background gamma spectra is minimized. The reduction of the gamma radiation background near the detector facilitates measurement of naturally occurring radioactive materials (NORM), and/or technologically enhanced NORM (TENORM), which are usually at concentration levels only slightly higher than those typically found in the natural radioactive background.

  6. Modern aerial gamma-ray spectrometry and regional potassium map of the conterminous United States

    USGS Publications Warehouse

    Duval, Joseph S.

    1990-01-01

    The aerial gamma-ray data were obtained as part of the National Uranium Resource Evaluation (NURE) Program sponsored by the U.S. Department of Energy during the period 1975-1983. References for the Open-File Reports that describe the surveys and data collection can be found in Bendix Field Engineering Corp. (1983). The aerial surveys were flown by contractors using fixed-wing and helicopter systems with 33-50 L (liters) of thallium-activated sodium iodide (NaI (TI)) crystals. The nominal survey altitude used is 122 m. The survey lines were generally east-west with line spacings of 1.6-10 km. Tie lines were flown perpendicular to the flight lines at intervals of 16- 30 km. The data were corrected for background from aircraft contamination and cosmic rays, altitude variations, airborne 214Bi, and Compton scattering. The gamma-ray systems were calibrated using the calibrations pads at Grand Junction, Colorado (Ward, 1978 ) and the dynamic test strip at Lake Mead, Arizona (Geodata International, Inc., 1977).  

  7. Status of the GERDA Phase II upgrade

    NASA Astrophysics Data System (ADS)

    Wagner, Victoria

    2016-06-01

    The GERDA experiment is designed to search for neutrinoless double beta (0νββ) decay of 76Ge. In Phase I of the experiment a background index of 10-2 cts/(keV.kg.yr) was reached. A lower limit on the half-life of the 0νββ decay of 76Ge was set to 2.1.1025 yr (at 90% C.L.). The aim of Phase II is to reach a sensitivity of the half-life of about 1026 yr. To increase the exposure thirty new Broad Energy Germanium (BEGe) detectors have been produced. These detectors are distinct for their improved energy resolution and enhanced pulse shape discrimination of signal from background events. Further background reduction will be reached by a light instrumentation to read out argon scintillation light. In April 2015 the light instrumentation together with eight BEGe detectors has been successfully deployed in the GERDA cryostat. In a commissioning run it was shown that two of the major background components, external γ-rays from 214Bi and 208Tl decays, were suppressed up to two orders of magnitude. We are confident to reach a background index of 10-3 cts/(keV.kg.yr) which is the design goal for GERDA Phase II.

  8. Measurements of gamma radiation levels and spectra in the San Francisco Bay Area

    NASA Astrophysics Data System (ADS)

    Lo, B. T.; Brozek, K. P.; Angell, C. T.; Norman, E. B.

    2011-10-01

    Much of the radiation received by an average person is emitted by naturally-occurring radioactive isotopes from the thorium, actinium, and uranium decay series, or potassium. In this study, we have measured gamma radiation levels at various locations in the San Francisco Bay Area and the UC Berkeley campus from spectra taken using an ORTEC NOMAD portable data acquisition system and a large-volume coaxial HPGe detector. We have identified a large number of gamma rays originating from natural sources. The most noticeable isotopes are 214Bi, 40K, and 208Tl. We have observed variations in counting rates by factors of two to five between different locations due to differences in local conditions - such as building, concrete, grass, and soil compositions. In addition, in a number of outdoor locations, we have observed 604-, 662-, and 795-keV gamma rays from 134,137Cs, which we attribute to fallout from the recent Fukushima reactor accident. The implications of these results will be discussed. This work was supported in part by a grant from the U. S. Dept. of Homeland Security.

  9. Natural radioactivity of the tar-sand deposits of Ondo State, Southwestern Nigeria

    NASA Astrophysics Data System (ADS)

    Fasasi, M. K.; Oyawale, A. A.; Mokobia, C. E.; Tchokossa, P.; Ajayi, T. R.; Balogun, F. A.

    2003-06-01

    A combination of gamma spectrometry and energy dispersive X-ray fluorescence was used to determine the presence and level of radioactivity of radionuclides in bituminous sand and overburden obtained from bituminous sand deposits in Ondo State Nigeria for the purpose of providing baseline data and assessing its impact on the environment. The radionuclides identified with reliable regularity belong to the decay series of naturally occurring radionuclides headed by 238U and 232Th. The non-decay series of naturally occurring 40K was found to be below the limit of detection. The average specific activity concentration values obtained for 214 Bi, 208Tl, and 226Ra in the overburden are 165.64±2.91, 150.25±2.91 and 60.97±2.27 Bq kg -1, respectively. The measured activity in the bituminous sand layer is so low that it can be said to be non-radioactive. The result of the EDXRF supports the presence of radioelements in the overburden, which are likely to be embedded in accessory minerals like zircon and tourmaline. Thus, surface exploration technique using soil-gas radon measurement will not yield the desired result. Furthermore, the level of radioelements and associated decay daughter 222Rn is not expected to cause any health hazard.

  10. Distribution and inventories of some artificial and naturally occurring radionuclides in medium to coarse-grained sediments of the channel

    NASA Astrophysics Data System (ADS)

    Boust, Dominique

    1999-12-01

    Concentrations of artificial ( 60Co, 137Cs, 238Pu and 239,240Pu) and naturally occurring radionuclides ( 40K, 212Pb and 214Pb, daughter nuclides of the 232Th and 238U series) in bottom sediments of the Channel are reported. They are grain-size modulated but usual grain-size normalisation methods fail due to the strong heterogeneity of the sediment admixture and/or the occurrence of rock debris in the area of concern. When plotted versus distance from Cap La Hague, 60Co and Pu isotope concentrations display a maximum in the Central Channel, but 137Cs do not. This is further explained by the contribution of the releases from the La Hague plant relative to other radionuclide inputs, especially Atlantic inflow and direct atmospheric fallout. Apparent transit times from Cap La Hague are derived from Pu isotopic ratios and yield average sediment velocities ranging from some kilometres to some tens of kilometres per year. Sediment inventories of artificial radionuclides show that a significant part of the input of 60Co and Pu isotopes is immobilised in the Channel seabed while most of the 137Cs input has been evacuated by water mass circulation.

  11. Assessment of natural and anthropogenic radioactivity levels in rocks and soils in the environs of Swieradow Zdroj in Sudetes, Poland, by in situ gamma-ray spectrometry.

    PubMed

    Malczewski, D; Teper, L; Dorda, J

    2004-01-01

    The natural radioactivity of 40K, 208Ti, 212Pb, 214Pb, 228Ac, and the fallout of 137Cs in typical rocks and soils of Swieradów Zdrój area (Sudetes Mountains, Poland) were measured in situ using a portable gamma-ray spectrometry workstation. The measurement points were chosen for different regional lithology: within hornfelses of the Szklarska Poreba schist-belt, quartz rocks, gneisses of the Swieradów Zdrój unit, leucogranites, leptinites, mica schists of the Stara Kamienica belt, and finally the zones of the southern and northern contacts of the Stara Kamienica schist-belt with leucogranites and gneisses of the Lesna unit, respectively. 40K activity varied in the range from about 320 Bq kg(-1) (quartz) to 1200 Bq kg(-1) (gneisses). The activity concentrations associated with 228Ac (232Th series) varied in the range from 25 Bq kg(-1) (quartz) to 62 Bq kg(-1) (leucogranites), whereas activity concentration of 226Ra varied in the range from about 31 Bq kg(-1) (hornfelses) to 122 Bq kg(-1) (leucogranites). Relatively low deposits of 137Cs were noted in the investigated area, where the activity concentrations ranged from 4001 (hornfelses) Bq m(-2) to less than 154 Bq m(-2) (leucogranites). PMID:15050357

  12. Radioactivity evaluation of Ebro river water and sludge treated in a potable water treatment plant located in the South of Catalonia (Spain).

    PubMed

    Palomo, M; Peñalver, A; Aguilar, C; Borrull, F

    2010-03-01

    A potable water treatment plant with an average production rate of 4.3m(3)/s, providing several cities in the south of Catalonia (Spain) with drinking water, has been studied for a period of six years (2002-2007) regarding its capacity to remove several natural and anthropogenic radionuclides. First, gross alpha, gross beta and tritium activities were determined in ingoing and outgoing water samples. The values for all these parameters were below the Spanish normative limits established for waters for human consumption. For the sludge samples generated in the plant, we quantified some gamma emitting radioisotopes: natural ((40)K, (214)Pb, etc.) and artificial ((60)Co, (110m)Ag, etc.) which may be related to the geological or/and industrial activities (such as a nuclear power plant) located upstream of the PWTP on the Ebro River. Finally, when the sludge samples were compared with those from other water treatment plants, the influence of the industrial activities on the radioisotopes found in the analysed samples was confirmed since the activity levels for some of the isotopes quantified were 10 times higher. PMID:20031431

  13. Multiple-scattering effects in nucleus-nucleus reactions with Glauber theory

    NASA Astrophysics Data System (ADS)

    Hatakeyama, Shinya; Ebata, Shuichiro; Horiuchi, Wataru; Kimura, Masaaki

    2014-09-01

    A study of new unstable nuclei has become possible in new radioactive beam facilities. In order to understand the relationship between reaction observables and nuclear structure, we need reaction theory which exactly reflects the nuclear structure. The Glauber theory is a powerful tool of analyzing high energy nuclear reactions. The theory describes the multiple scattering processes, whereas the optical limit approximation (OLA), which is widely used, ignores those processes. Those effects are expected to play an important role in the nuclear collision involving unstable nuclei (see for example Phys. Rev. C 54, 1843 (1996)). Here we apply the Glauber theory to nucleus-nucleus reactions. The wave functions are generated by the Skyrme-Hartree-Fock method and are expressed in a Slater determinant that allows us to evaluate the complete Glauber amplitude easily. We calculate total reaction cross sections, elastic cross sections and differential elastic cross sections for 16~24O, 40~70Ca, 56,58Ni, 100~140Sn, 190~214Pb on proton, 4He, 12C targets and compare with experimental data. The Glauber theory gives much better description than the OLA, especially at larger scattering angles.

  14. Monte Carlo simulation of a PhosWatch detector using Geant4 for xenon isotope beta-gamma coincidence spectrum profile and detection efficiency calculations.

    PubMed

    Mekarski, P; Zhang, W; Ungar, K; Bean, M; Korpach, E

    2009-10-01

    A simulation tool has been developed using the Geant4 Toolkit to simulate a PhosWatch single channel beta-gamma coincidence detection system consisting of a CsI(Tl)/BC404 Phoswich well detector and pulse shape analysis algorithms implemented digital signal processor. The tool can be used to simulate the detector's response for all the gamma rays and beta particles emitted from (135)Xe, (133m)Xe, (133)Xe, (131m)Xe and (214)Pb. Two- and three-dimensional beta-gamma coincidence spectra from the PhosWatch detector can be produced using the simulation tool. The accurately simulated spectra could be used to calculate system coincidence detection efficiency for each xenon isotope, the corrections for the interference from the various spectral components from radon and xenon isotopes, and system gain calibration. Also, it can generate two- and three-dimensional xenon reference spectra to test beta-gamma coincidence spectral deconvolution analysis software. PMID:19647444

  15. Properties of 220Rn progeny (212Pb) in the presence of trace gases.

    PubMed

    Wang, M Y; Phillips, C R

    1992-03-01

    The charge neutralization of 220Rn progeny (212Pb) was studied in nitrogen and argon environments containing trace concentrations of ethylene, propylene and propane. The diffusion coefficient of 212Pb atoms in the presence and in the absence of oxygen and hydrocarbons was determined using a diffusion tube method which measured the penetration fraction of the 220Rn decay products. The results are explained in terms of the formation of lead dioxide with an ionization potential in the range of 10.5-11.1 eV. The ionization potential of 212PbO2 was found to be higher than that of 218PoO2. Charge neutralization was found to occur in a gas mixture of argon and oxygen containing 600 ppm ethylene (C2H4) and also in a mixture of nitrogen and oxygen containing 600 ppm propylene (C3H6). Charge neutralization was not found to occur in a mixture of argon and oxygen containing up to 5000 ppm propane (C3H8) and in a mixture of argon and nitrogen containing 600 ppm ethylene. In pure oxygen, nitrogen, argon, dry air and a mixture of nitrogen and oxygen, no neutralization was observed to occur through charge transfer from neutral molecules. The 220Rn concentration was found to influence the neutralization mechanism. Diffusion coefficients for partially neutralized and neutralized 212Pb ranged from 0.050 to 0.067 cm2 s-1 at a 220Rn concentration of 3.7 x 10(4) atoms cm-3 and a relative humidity of less than 5%. PMID:1566046

  16. Retrospective assessment of indoor radon exposure by measurements of embedded 210Po activity in glass objects

    NASA Astrophysics Data System (ADS)

    Ramola, R. C.; Gusain, G. S.; Prasad, Ganesh

    In most of the epidemiological studies contemporary radon measurements have been used as surrogates for radon concentrations in past decades even though changes in radon levels and residence may have occurred. Short-lived radon progeny may deposit on available surfaces in dwellings thus giving rise over time to a build up of long-lived progeny. Airborne radon decay products can be deposited and implanted through alpha recoil into the glass surfaces. On glass surface, activities of 210Po may arise as a result of the decay of recoil implanted activity following the alpha decay of surface deposited 218Po or 214Po. Measurement of 210Po implanted on a household glass is a method that can be employed to retrospectively determine the historic level of radon in dwellings. This method is based on the assumption that levels of recoil implanted 210Po in the glass provide a measure of time integrated radon concentration in the environment in which the glass has been located. The surface deposited activity of the radon progenies, which then become implanted in the glass by alpha recoil, is believed to reflect past exposure to airborne activity. Such retrospective measurements on glass are valuable in estimating the human dose derived from radon during the time of exposure. In this paper an account is given of the principles and some field applications of a retrospective technique, using the alpha track detectors, CR-39 and LR-115, to measure 210Po implanted in glass surfaces (surface traps). By using this CR-LR difference technique, the cumulative radon exposure in a dwelling in past decades may be estimated. This method provides reliable radon exposure data as a support to epidemiological studies concerning the health effects of radon exposure in the living environment.

  17. Radioisotope Deposition on Interior Building Surfaces: Air Flow and Surface Roughness Influences

    SciTech Connect

    Leonard, Bobby E

    2005-12-15

    Interior surface deposition effects of vaporized radioactive aerosols are important in understanding their behavior in accident conditions such as the Japanese nuclear laboratory accident in 1999 and the Chernobyl nuclear power plant accident in 1986, where entire communities had to be abandoned because of surface contamination, and the hopefully unlikelihood of a terrorist dirty nuclear bomb attack. Airborne radon progeny offers an opportunity to study radioisotope surface deposition. A significant annual lung cancer rate is also attributed to airborne radon progeny in the interior domestic environment. Surface deposition rates influence the airborne progeny levels. Here, we report extensive {sup 218}Po deposition rates over typical air change rates (ACHs) from 0.02 to 1.0 h{sup -1} for interior furnishings surfaces in a 0.283-m{sup 3} test chamber to supplement earlier reported deposition rates for interior wall, ceiling, and floor surfaces. In analyzing the deposition results from the different materials, it is found that they correlate in terms of roughness with relative static friction and aerodynamic shear stress. Extrapolation to perfectly smooth surfaces provides a good estimate of the Fick's law value. Contrary to prior radon analysis at higher air flow, where the Crump and Seinfeld (CS) turbulent deposition models seemed to fit, at low ACH below 0.5 h{sup -1} the deposition data found excellent agreement with a new Brownian diffusive deposition model for laminar flow. A composite model using the Brownian diffusive laminar flow and the CS turbulent flow models provides an excellent fit to all data. These results provide insight into contamination issues relative to other airborne radioisotopes, with the relative effects being dependent on the airborne contaminant particle sizes and their respective diffusion coefficients as seen in the two deposition models.

  18. Radon permeability and radon exhalation of building materials.

    PubMed

    Keller, G; Hoffmann, B; Feigenspan, T

    2001-05-14

    High radon concentrations indoors usually depend on the possibilities of radon penetration from the surrounding soil into the buildings. Radon concentrations in dwellings up to 100 kBq/m3 were found in some special regions (i.e. Schneeberg/Saxony, Umhausen/Tyrol), where the soil shows a high uranium content and additionally, a fast radon transport in the soil is possible. To reduce the radon exposure of the inhabitants in these 'radon prone areas' it is necessary to look for building and insulating materials with low radon permeability. We examined several building materials, like cements, concretes and bricks of different constitutions for their diffusion coefficients and their exhalation rates. The insulating materials, like foils and bitumen were tested also on their radon tightness. The measurements were performed with an online radon measuring device, using electrostatic deposition of 218Po ions onto a surface barrier detector and subsequent alpha spectroscopy. The mean diffusion lengths for the investigated building materials range from lower than 0.7 mm (i.e. for plastic foil), up to 1.1 m for gypsum. The diffusion length R was calculated from the diffusion coefficient D with R = square root(D/lambda). If the thickness of the material is more than 3 times the diffusion length, then it is called radon-tight. The mean 222Rn exhalation rates for the building materials varied between 0.05 and 0.4 mBq/m2s. The samples were investigated as stones, plates, blocks, foils, coatings, powders etc., no statement can be made about working at the construction site of a building. Also the fabrication and processing of the materials has to be considered, because the material characteristics may have changed. PMID:11379942

  19. Measurement of (222)Rn by absorption in plastic scintillators and alpha/beta pulse shape discrimination.

    PubMed

    Mitev, Krasimir K

    2016-04-01

    This work demonstrates that common plastic scintillators like BC-400, EJ-200 and SCSF-81 absorb radon and their scintillation pulse decay times are different for alpha- and beta-particles. This allows the application of pulse shape analysis for separation of the pulses of alpha- and beta-particles emitted by the absorbed radon and its progeny. It is shown that after pulse shape discrimination of beta-particles' pulses, the energy resolution of BC-400 and EJ-200 alpha spectra is sufficient to separate the peaks of (222)Rn, (218)Po and (214)Po and allows (222)Rn measurements that are unaffected by the presence of thoron ((220)Rn) in the environment. The alpha energy resolution of SCSF-81 in the experiments degrades due to imperfect collection of the light emitted inside the scintillating fibers. The experiments with plastic scintillation microspheres (PSM) confirm previous findings of other researchers that PSM have alpha-/beta-discrimination properties and show suitability for radon measurements. The diffusion length of radon in BC-400 and EJ-200 is determined. The pilot experiments show that the plastic scintillators are suitable for radon-in-soil-gas measurements. Overall, the results of this work suggest that it is possible to develop a new type of radon measurement instruments which employ absorption in plastic scintillators, pulse-shape discrimination and analysis of the alpha spectra. Such instruments can be very compact and can perform continuous, real-time radon measurements and thoron detection. They can find applications in various fields from radiation protection to earth sciences. PMID:26851823

  20. Natural radioactivity contents in tobacco and radiation dose induced from smoking.

    PubMed

    Shousha, Hany A; Ahmad, Fawzia

    2012-06-01

    One of the causative factors for cancer-inducing mechanisms in humans is radioactive elements present in tobacco leaves used in the manufacture of cigarettes. Smoking of tobacco and its products increases the internal intake and radiation dose due to naturally occurring radionuclides that are considered to be one of the most significant causes of lung cancer. In this work, different commercial types of cigarettes, cigar and moassel were collected from market. Naturally occurring radionuclides (226)Ra and (214)Bi ((238)U series), (228)Ac and (228)Ra ((232)Th series), (40)K  and man-made (137)Cs were measured in tobacco using gamma-ray spectrometer. Results show that the average concentrations of (238)U, (232)Th and (40)K were 4.564, 3.940 and 1289.53 Bq kg(-1), respectively. This reflects their origin from the soil by root uptake and fertilisers used in the cultivation of tobacco plants. Concentration of (137)Cs was 0.348 Bq kg(-1) due to root uptake or deposition onto the leaf foliage. For smokers, the annual effective dose due to inhalation of (238)U varied from 49.35 to 139.40 μSv(-1) (average 104.27 μSv y(-1)), while of (232)Th from 23.86 to 111.06 μSv y(-1) (average 65.52 μSv y(-1)). The annual effective dose resulting from (137)Cs was varied from 10.96 to 24.01 nSv y(-1) (average 19.41 nSv y(-1)). PMID:21926418

  1. Chemical inputs from a karstic submarine groundwater discharge (SGD) into an oligotrophic Mediterranean coastal area.

    PubMed

    Pavlidou, Alexandra; Papadopoulos, Vassilis P; Hatzianestis, Ioannis; Simboura, Nomiki; Patiris, Dionisis; Tsabaris, Christos

    2014-08-01

    The impacts of nutrient and other chemical inputs released by a submarine groundwater discharge (SGD) on the marine environment of an oligotrophic Mediterranean coastal area (Messiniakos Gulf, SE Ionian Sea) are investigated through a multidisciplinary approach. Nutrients and organic pollutants associated with the SGD are presented to study the chemical characteristics of the SGD and to investigate its effect on the marine ecosystem in comparison to freshwater discharges of the water bodies of Messinia Prefecture. Nutrient and organic pollutant fluxes were calculated from (214)Bi-based SGD estimates. An average of 22×10(3) mol of silicate per month and 8×10(3) mol of nitrate per month were released via the SGD. Nutrient concentrations at the mouth of the SGD were three times higher than in Messiniakos Gulf, and NO3(-) was the primary Dissolved Inorganic Nitrogen form discharged by SGD. Organic pollutant concentrations associated with agricultural activities were low at the SGD. The implementation of a Eutrophication Index (E.I.) showed that the water column at the SGD site corresponds to Moderate/Bad ecological quality, whereas the status switches rapidly to Good at a small distance from the SGD. Coastal areas influenced by river or sewage discharge correspond to a Moderate/Good ecological status. The BENTIX index used for the classification of the ecological quality status of the benthic macroinvertebrate communities showed that the SGD has a minor influence compared to the other freshwater discharges in Messiniakos Gulf. Though the SGD has a considerable outflow, morphology and hydrodynamics of the area favor the rapid dispersion of the upwelling water and degrades the SGD's effect even on a regional scale. PMID:24814032

  2. Experimental study of radon production and transport in an analogue for the Martian regolith

    NASA Astrophysics Data System (ADS)

    Meslin, P. Y.; Sabroux, J. C.; Bassot, S.; Chassefière, E.

    2011-05-01

    The suggestion that radon could be used as a radioactive tracer of regolith-atmosphere exchanges and as a proxy for subsurface water on Mars, as well as its indirect detection in the Martian atmosphere by the rover Opportunity, have raised the need for a better characterization of its production process and transport efficiency in the Martian soil. More specifically, a proper estimation of radon exhalation rate on Mars requires its emanation factor and diffusion length to be determined. The dependence of the emanation factor as a function of pore water content (at 267 and 293 K) and the dependence of the adsorption coefficient on temperature, specific surface area and nature of the carrier gas (He, He + CO 2) have been measured on a Martian soil analogue (Hawaiian palagonitized volcanic ash, JSC Mars-1), whose radiometric analysis has been performed. An estimation of radon diffusion lengths on Mars is provided and is used to derive a global average emanation factor (2-6.5%) that accounts for the exhalation rate inferred from the 210Po surface concentration detected on Martian dust and from the 214Bi signal measured by the Mars Odyssey Gamma Ray Spectrometer. It is found to be much larger than emanation factors characterizing lunar samples, but lower than the emanation factor of the palagonite samples obtained under dry conditions. This result probably reflects different degrees of aqueous alteration and could indicate that the emanation factor is also affected by the current presence of pore water in the Martian soil. The rationale of the "radon method" as a technique to probe subsurface water on Mars, and its sensitivity to soil parameters are discussed. These experimental data are useful to perform more detailed studies of radon transport in the Martian atmosphere using Global Climate Models and to interpret neutron and gamma data from Mars Odyssey Gamma Ray Spectrometer.

  3. Determination of strontium-90 from direct separation of yttrium-90 by solid phase extraction using DGA Resin for seawater monitoring.

    PubMed

    Tazoe, Hirofumi; Obata, Hajime; Yamagata, Takeyasu; Karube, Zin'ichi; Nagai, Hisao; Yamada, Masatoshi

    2016-05-15

    It is important for public safety to monitor strontium-90 in aquatic environments in the vicinity of nuclear related facilities. Strontium-90 concentrations in seawater exceeding the background level have been observed in accidents of nuclear facilities. However, the analytical procedure for measuring strontium-90 in seawater is highly demanding. Here we show a simple and high throughput analytical technique for the determination of strontium-90 in seawater samples using a direct yttrium-90 separation. The DGA Resin is used to determine the abundance of strontium-90 by detecting yttrium-90 decay (beta-emission) in secular equilibrium. The DGA Resin can selectively collect yttrium-90 and remove naturally occurring radionuclides such as (40)K, (210)Pb, (214)Bi, (238)U, and (232)Th and anthropogenic radionuclides such as (140)Ba, and (140)La. Through a sample separation procedure, a high chemical yield of yttrium-90 was achieved at 95.5±2.3%. The result of IAEA-443 certified seawater analysis (107.7±3.4 mBq kg(-1)) was in good agreement with the certified value (110±5 mBq kg(-1)). By developed method, we can finish analyzing 8 samples per day after achieving secular equilibrium, which is a reasonably fast throughput in actual seawater monitoring. By processing 3 L of seawater sample and applying a counting time of 20 h, minimum detectable activity can be as low as 1.5 mBq kg(-1), which could be applied to monitoring for the contaminated marine environment. Reproducibility was found to be 3.4% according to 10 independent analyses of natural seawater samples from the vicinity of the Fukushima Daiichi Nuclear Power Plant in September 2013. PMID:26992514

  4. Radioactive Aerosols as an Index of Air Pollution in the City of Thessaloniki, Greece

    NASA Astrophysics Data System (ADS)

    Ioannidou, A.; Papastefanou, C.

    2010-01-01

    This study summarizes results of an investigation done in order to find out how the radioactive aerosols of 7Be could serve as indicators of air pollution conditions. Beryllium-7 is a cosmic-ray produced radionuclide with an important fraction of its production to take place in the upper troposphere. Once it is formed is rapidly associated with submicron aerosol particles and participates in the formation and growth of the accumulation mode aerosols, which is a major reservoir of pollutants in the atmosphere. In order to define any influence of AMAD of 7Be aerosols by air pollution conditions, the aerodynamic size distribution of 7Be aerosols was determined by collecting samples at different locations in the suburban area of the city of Thessaloniki, including rural areas, industrial areas, high elevations, marine environment and the airport area. The aerodynamic size distribution of 7Be aerosols in different locations was obtained by using Andersen 1-ACFM cascade impactors and the Activity Median Aerodynamic Diameter (AMAD) was determined. Some dependency of the AMADs on height has been observed, while in near marine environment the 7Be activity size distribution was dominant in the upper size range of aerosol particles. Low AMADs as low as 0.62 to 0.74 μm of 7Be aerosols have been observed at locations characterized with relative low pollution, while it is concluded that in the activity size distribution of ambient aerosols, 7Be changes to larger particle sizes in the presence of pollutants, since low AMADs of 7Be aerosols have been observed at low polluted locations. Preliminary data of simultaneous measurements of 214Pb and 212Pb with gaseous air pollutants CO, NO, NOX, SO2 and total suspended particulate matter (TSP) show that radon decay products near the ground could be a useful index of air pollution potential conditions and transport processes in the boundary layer.

  5. The cumulative effect of three decades of phosphogypsum amendments in reclaimed marsh soils from SW Spain: (226)Ra, (238)U and Cd contents in soils and tomato fruit.

    PubMed

    Abril, José-María; García-Tenorio, Rafael; Enamorado, Santiago M; Hurtado, M Dolores; Andreu, Luis; Delgado, Antonio

    2008-09-15

    Phosphogypsum (PG), a by-product of the phosphate fertiliser industries, has been applied as soil amendment to reduce Na saturation in soils, as in the reclaimed marsh area from SW Spain, where available PG has a typical fingerprint of 710+/-40 Bq kg(-1) of (226)Ra, 165+/-15 Bq kg(-1) of (238)U and 2.8+/-0.4 mg kg(-1) of Cd. This work was focussed on the cumulative effects of PG amendments on the enrichment of these pollutants in cultivated soils and plants (Lycopersicum esculentum Mill L.) from the area studied, where PG has been applied since 1978 at recommended rates of 20-25 Mg ha(-1) every 2-3 years. A field experiment was conducted over three years to compare activity concentrations of (226)Ra ((214)Pb) and (238)U ((234)Th) in non-reclaimed soils, reclaimed soils with no additional PG application, and reclaimed soils with two additional PG applications. A non-significant effect of two PG amendments (in three years) was observed when compared with non-amended reclaimed plots. Nevertheless, a significant (p<0.05) enrichment of (226)Ra was observed in the surface horizon (0-30 cm) of reclaimed plots relative to deeper horizons and also when compared with the surface horizon of non-reclaimed soil (p<0.05), thereby revealing the cumulative effect of three decades of PG applications. Furthermore, the effect of a continuous application of PG was studied by analysing soils and tomato fruits from six commercial farms with different cumulative rates of PG applied. Cadmium concentrations in tomatoes, which were one order of magnitude higher than those found in tomatoes from other areas in South Spain, were positively correlated (r = 0.917) with (226)Ra-concentration in soils, which can be considered an accurate index of the cumulative PG rate of each farm. PMID:18602676

  6. Evaluation of the anthropogenic radionuclide concentrations in sediments and fauna collected in the Beaufort Sea and northern Alaska

    SciTech Connect

    Efurd, D.W.; Miller, G.G.; Rokop, D.J.

    1997-07-01

    This study was performed to establish a quality controlled data set about the levels of radio nuclide activity in the environment and in selected biota in the U.S. Arctic. Sediment and biota samples were collected by the National Oceanic and Atmospheric Administration (NOAA), the National Biological Service, and the North Slope Borough`s Department of Wildlife Management to determine the impact of anthropogenic radionuclides in the Arctic. The results summarized in this report are derived from samples collected in northwest Alaska with emphasis on species harvested for subsistence in Barrow, Alaska. Samples were analyzed for the anthropogenic radionuclides {sup 90}Sr, {sup 137}Cs, {sup 238}Pu, {sup 239}Pu, {sup 240}Pu and {sup 241}Am. The naturally occurring radionuclides {sup 40}K, {sup 212}Pb and {sup 214}Pb were also measured. One goal of this study was to determine the amounts of anthropogenic radionuclides present in the Beaufort Sea. Sediment samples were isotopically fingerprinted to determine the sources of radio nuclide activities. Biota samples of subsistence and ecological value were analyzed to search for evidence of bio-accumulation of radionuclides and to determine the radiation exposures associated with subsistence living in northern Alaska. The anthropogenic radio nuclide content of sediments collected in the Beaufort Sea was predominantly the result of the deposition of global fallout. No other sources of anthropogenic radionuclides could be conclusively identified in the sediments. The anthropogenic radio nuclide concentrations in fish, birds and mammals were very low. Assuming that ingestion of food is an important pathway leading to human contact with radioactive contaminants and given the dietary patterns in coastal Arctic communities, it can be surmised that marine food chains are presently not significantly affected.

  7. Radon Dose Determination for Cave Guides in Czech Republic

    NASA Astrophysics Data System (ADS)

    Thinova, Lenka; Rovenska, Katerina

    2008-08-01

    According to recommended approach there are six (from total of twelve) open-to-public caves in Czech Republic, reaching near to an effective lung-dose of 6mSv/year. A conservative approach for estimating the potential effective lung-dose in caves (or underground) is based on two season's measurements, using solid state alpha track detector (Kodak in plastic diffusion chamber). The obtained dataset is converted into an annual effective dose, in agreement with the ICRP65 recommendation, using the "cave factor" 1.5. The value of "cave factor" which depends on the spectrum of aerosol particles, or on the proportional representation of the unattached/attached ratio (6.5 : 93.5 for residential places, 13.6 : 86.4 for caves due to lower concentration of free aerosols) and on the equilibrium factor. Thus conversion factor is 1.5 times higher in comparison with ICRP 65. Is this correct? Because a more precisely determined dose value would have a significant impact on radon remedies, or on restricting the time workers stay underground, a series of measurement was initiated in 2003 with the aim to specify input data, computation and errors in effective dose assessment in each one of the evaluated caves separately. The enhancement of personal dosimetry for underground work places includes a study of the given questions, from the following points of view in each cave: continual radon measurement; regular measurements of radon and its daughters to estimate the equilibrium factor and the presence of free 218Po; regular indoor air flow measurements to study the location of the radon supply and its transfer among individual areas of the cave; natural radioactive element content evaluation in subsoil and in water inside/outside, a study of the radon sources in the cave; determination of the free fraction from continual unattached and attached fraction measurement (grid and filter); thoron measurement. Air flow measurements provide very interesting information about the origin of

  8. Radon Dose Determination for Cave Guides in Czech Republic

    SciTech Connect

    Thinova, Lenka; Rovenska, Katerina

    2008-08-07

    According to recommended approach there are six (from total of twelve) open-to-public caves in Czech Republic, reaching near to an effective lung-dose of 6mSv/year. A conservative approach for estimating the potential effective lung-dose in caves (or underground) is based on two season's measurements, using solid state alpha track detector (Kodak in plastic diffusion chamber). The obtained dataset is converted into an annual effective dose, in agreement with the ICRP65 recommendation, using the 'cave factor' 1.5. The value of 'cave factor' which depends on the spectrum of aerosol particles, or on the proportional representation of the unattached/attached ratio (6.5 : 93.5 for residential places, 13.6 : 86.4 for caves due to lower concentration of free aerosols) and on the equilibrium factor. Thus conversion factor is 1.5 times higher in comparison with ICRP 65. Is this correct? Because a more precisely determined dose value would have a significant impact on radon remedies, or on restricting the time workers stay underground, a series of measurement was initiated in 2003 with the aim to specify input data, computation and errors in effective dose assessment in each one of the evaluated caves separately. The enhancement of personal dosimetry for underground work places includes a study of the given questions, from the following points of view in each cave: continual radon measurement; regular measurements of radon and its daughters to estimate the equilibrium factor and the presence of free {sup 218}Po; regular indoor air flow measurements to study the location of the radon supply and its transfer among individual areas of the cave; natural radioactive element content evaluation in subsoil and in water inside/outside, a study of the radon sources in the cave; determination of the free fraction from continual unattached and attached fraction measurement (grid and filter); thoron measurement. Air flow measurements provide very interesting information about the origin

  9. Modeling Background Attenuation by Sample Matrix in Gamma Spectrometric Analyses

    SciTech Connect

    Bastos, Rodrigo O.; Appoloni, Carlos R.

    2008-08-07

    In laboratory gamma spectrometric analyses, the procedures for estimating background usually overestimate it. If an empty container similar to that used to hold samples is measured, it does not consider the background attenuation by sample matrix. If a 'blank' sample is measured, the hypothesis that this sample will be free of radionuclides is generally not true. The activity of this 'blank' sample is frequently sufficient to mask or to overwhelm the effect of attenuation so that the background remains overestimated. In order to overcome this problem, a model was developed to obtain the attenuated background from the spectrum acquired with the empty container. Beyond reasonable hypotheses, the model presumes the knowledge of the linear attenuation coefficient of the samples and its dependence on photon energy and samples densities. An evaluation of the effects of this model on the Lowest Limit of Detection (LLD) is presented for geological samples placed in cylindrical containers that completely cover the top of an HPGe detector that has a 66% relative efficiency. The results are presented for energies in the range of 63 to 2614keV, for sample densities varying from 1.5 to 2.5 g{center_dot}cm{sup -3}, and for the height of the material on the detector of 2 cm and 5 cm. For a sample density of 2.0 g{center_dot}cm{sup -3} and with a 2cm height, the method allowed for a lowering of 3.4% of the LLD for the energy of 1460keV, from {sup 40}K, 3.9% for the energy of 911keV from {sup 228}Ac, 4.5% for the energy of 609keV from {sup 214}Bi, and8.3% for the energy of 92keV from {sup 234}Th. For a sample density of 1.75 g{center_dot}cm{sup -3} and a 5cm height, the method indicates a lowering of 6.5%, 7.4%, 8.3% and 12.9% of the LLD for the same respective energies.

  10. 238U, and its decay products, in grasses from an abandoned uranium mine

    NASA Astrophysics Data System (ADS)

    Childs, Edgar; Maskall, John; Millward, Geoffrey

    2016-04-01

    Bioaccumulation of radioactive contaminants by plants is of concern particularly where the sward is an essential part of the diet of ruminants. The abandoned South Terras uranium mine, south west England, had primary deposits of uraninite (UO2) and pitchblende (U3O8), which contained up to 30% uranium. When the mine was active uranium and radium were extracted but following closure it was abandoned without remediation. Waste rock and gangue, consisting of inefficiently processed minerals, were spread around the site, including a field where ruminants are grazed. Here we report the activity concentrations of 238U, 235U 214,210Pb, and the concentrations of selected metals in the soils, roots and leaves of grasses taken from the contaminated field. Soil samples were collected at the surface, and at 30 cm depth, using an auger along a 10-point transect in the field from the foot of a waste heap. Whole, individual grass plants were removed with a spade, ensuring that their roots were intact. The soils and roots and grass leaves were freeze-dried. Activity concentrations of the radionuclides were determined by gamma spectroscopy, following 30 days incubation for development of secular equilibrium. Dried soils, roots and grasses were also digested in aqua regia and the concentrations of elements determined by ICP techniques. Maximum activity concentrations of 238U, 235U, 214Pb and 210Pb surface soils were 63,300, 4,510, 23,300 and 49,400 Bq kg‑1, respectively. The mean 238U:235U ratio was 11.8 ± 1.8, an order of magnitude lower than the natural value of 138, indicating disequilibrium within the decay chain due to mineral processing. Radionuclides in the roots had 5 times lower concentration and only grass leaves in the vicinity of the waste heap had measureable values. The mean soil to root transfer factor for 238U was 36%, the mean root to leaf was 3% and overall only 0.7% of 238U was transferred from the soil to the leaves. The roots contained 0.8% iron, possibly as

  11. The exogenous particles of heavy metals and/or radionuclide interaction with cellular organelles in Phragmites australis (Cav.) Steudel leaf

    NASA Astrophysics Data System (ADS)

    Corneanu, Gabriel; Corneanu, Mihaela; Craciun, Constantin; Tripon, Septimiu

    2013-04-01

    Phragmites australis (Cav.) Steudel (reed), is a phytoremediatory species, meet in the swampy areas, being a hypperaccumulator for chromium (Calheiros et al., 2008; Ait Ali et al., 2004, a/o). In nature there are cytotypes with a different somatic chromosome number (6x - 16x), with a good adaptation at various environmental conditions. Weis and Weis (2004) consider that reed is an invasive species, sequester more metals than some native species and recommended to use it, in wetlands, for phytoremediation and marsh restoration. Researches performed by Hakmaoui et al. (2007) regarding the ultrastructural effect of cadmium and cooper on reed, evidenced the presence of the ferritin aggregates in the chloroplast stroma, as well as some reversible modifications in chloroplast. In this paper, the ultrastructural features of the leaf in three Phragmites australis genotypes, from the Middle Jiu river valley (Gorj county, Romania), were analyzed: Control (Ţânţăreni village); a population from neighbourhood of TEPP-Turceni; and other population developed at the basis a sterile waste dump of 40 years-old (near Cocoreni village). The heavy metal and radionuclide content of the soil was different in the three sites, with the lowest values in Control and the highest values for many heavy metals (Zn, Mn, Ni, Co, Cd) and radionuclide's (U-238, Ra-226, Pb-210, Bi-214, Pb-214, U-235, Ac-228, Pb-212, Cs-137) on the sterile waste dump. The analysis of the ultrastructural features of the leaf in mature plants revealed some differences between the three Phragmites australis genotypes. The ultrastructural investigations underlined the adaptation of this species against the stress factors (heavy metals and radionuclides). The exogenous particles penetrated the foliar tissue through the epidermis and stomata, being spread in the cells, at the plasmodesmata level, through endoplasmic reticulum, and through the vascular system. The exogenous particles were present on the endoplasmic

  12. Constraints for Using Radon-in-Water Concentrations as an Indicator for Groundwater Discharge into Surface Water Bodies

    NASA Astrophysics Data System (ADS)

    Petermann, Eric; Schubert, Michael

    2015-04-01

    The radon (222-Rn) activity concentration of surface water is a favourable indicator for the detection of groundwater discharge into surface water bodies since radon is highly enriched in groundwater relative to surface waters. Hence, positive radon-in-water anomalies are interpreted as groundwater discharge locations. For this approach, usually, radon time-series are recorded along transects in near-surface waters. Time-series of radon-in-water concentration are commonly measured by permanent radon extraction from a water pump stream and continuous monitoring of the resulting radon-in-air concentration by means of a suitable radon detector. Radon-in-water concentrations are derived from the recorded radon-in-air signal by making allowances for water/air partitioning of radon. However, several constraints arise for this approach since undesirable factors are influencing the radon-in-water concentration. Consequently, corrections are required to remove the effect of these undesirable factors from the radon signal. First, an instrument inherent response delay between actual changes in the radon-in-water concentration and the related radon-in-air signal was observed during laboratory experiments. The response delay is due to (i) the water/air transfer kinetics of radon and (ii) the delayed decay equilibrium between radon and its progeny polonium (218-Po), which is actually being measured by most radon-in-air monitors. We developed a physical model, which considers all parameters that are responsible for the response delay. This model allows the reconstruction of radon-in-water time-series based on radon-in-air records. Second, on a time-scale of several hours the tidal stage is known as a major driver for groundwater discharge fluctuations due to varying hydraulic gradients between groundwater and surface water during a tidal cycle. Consequently, radon-in-water time-series that are detected on tidal coasts are not comparable among each other without normalization

  13. Cosmogenic Effects in Bouvante Eucrite

    NASA Astrophysics Data System (ADS)

    Bhandari, N.; Bonino, G.; Cini Castagnoli, G.

    1992-07-01

    of more than 13 years of the fall of the meteorite. The measured activities, at the time the meteorite was found are ^26Al = 91.6+-0.7 dpm/kg, ^22Na = 76.0+-7 dpm/kg and ^44Ti = 2.1+-0.5 dpm/kg. Upper limits of 0.8 dpm/kg were obtained for ^60Co and of 0.05 dpm/kg for ^42Ar. Uranium also could be estimated via its daughter ^214Bi to be ~200 ppb. The results could be compared with activities in another eucrite Bereba where a 400-g fragment was counted in a similar manner. The track density and the low ^60Co activity suggests that the meteorite was exposed as a small body (R(sub)pre ~=21 cm) in space. Measured activity of ^22Na is close to the expected value, when corrected for solar cycle modulation, and indicates that the meteorite did not fall much before the time it was found. We are grateful to Drs. P. Pellas and B. Zanda of the Muse de History Naturelle, Paris, for loaning us the Bouvante and Bereba meteorites. We thank Mr. K. M. Suthar for assistance in track analysis. References: Bonino G., Cini Castagnoli G., and Bhandari N. (1991) Il Nuovo Cimento (1991) (submitted); Michel Levy C., Bourot Denise M., Palme H., Spettel B., and Wanke H. (1987) Bull. Mineral., 110, 449; Weber H. W., Braun O., Schultz L., and Begemann F. (1983) Z. Naturforsch, 38a, 267.

  14. Modeling of U-series Radionuclide Transport Through Soil at Pena Blanca, Chihuahua, Mexico

    NASA Astrophysics Data System (ADS)

    Pekar, K. E.; Goodell, P. C.; Walton, J. C.; Anthony, E. Y.; Ren, M.

    2007-05-01

    The Nopal I uranium deposit is located at Pena Blanca in Chihuahua, Mexico. Mining of high-grade uranium ore occurred in the early 1980s, with the ore stockpiled nearby. The stockpile was mostly cleared in the 1990s; however, some of the high-grade boulders have remained there, creating localized sources of radioactivity for a period of 25-30 years. This provides a unique opportunity to study radionuclide transport, because the study area did not have any uranium contamination predating the stockpile in the 1980s. One high-grade boulder was selected for study based upon its shape, location, and high activity. The presumed drip-line off of the boulder was marked, samples from the boulder surface were taken, and then the boulder was moved several feet away. Soil samples were taken from directly beneath the boulder, around the drip-line, and down slope. Eight of these samples were collected in a vertical profile directly beneath the boulder. Visible flakes of boulder material were removed from the surficial soil samples, because they would have higher concentrations of U-series radionuclides and cause the activities in the soil samples to be excessively high. The vertical sampling profile used 2-inch thicknesses for each sample. The soil samples were packaged into thin plastic containers to minimize the attenuation and to standardize sample geometry, and then they were analyzed by gamma-ray spectroscopy with a Ge(Li) detector for Th-234, Pa-234, U-234, Th-230, Ra-226, Pb-214, Bi-214, and Pb-210. The raw counts were corrected for self-attenuation and normalized using BL-5, a uranium standard from Beaverlodge, Saskatchewan. BL-5 allowed the counts obtained on the Ge(Li) to be referenced to a known concentration or activity, which was then applied to the soil unknowns for a reliable calculation of their concentrations. Gamma ray spectra of five soil samples from the vertical profile exhibit decreasing activities with increasing depth for the selected radionuclides

  15. Groundwater Monitoring and Control Before Decommissioning of the Research Reactor VVR-S from Magurele-Bucharest

    SciTech Connect

    Dragusin, Mitica

    2008-01-15

    The research reactor type VVR-S (tank type, water is cooler, moderator and reflector, thermal power- 2 MW, thermal energy- 9. 52 GW d) was put into service in July 1957 and, in December 1997 was shout down. In 2002, Romanian Government decided to put the research reactor in the permanent shut-down in order to start the decommissioning. This nuclear facility was used in nuclear research and radioisotope production for 40 years, without events, incidents or accidents. Within the same site, in the immediate vicinity of the research reactor, there are many other nuclear facilities: Radioactive Waste Treatment Plant, Tandem Van der Graaf heavy ions accelerator, Cyclotron, Industrial Irradiator, Radioisotope Production Center. The objectives of this work were dedicated on the water underground analyses described in the following context: - presentation of the approaches in planning the number of drillings, vertical soil profiles (characteristics, analyses, direction of the flow of underground water, uncertainties in measurements); - presentation of the instrumentation used in analyses of water, soil and vegetation samples - analyses and final conclusions on results of the measurements; - comparison of the results of measurements on underground water from drillings with the measurements results on samples from the town and the system of drinking water - supplied from the second level of underground water. According to the analysis, in general, no values higher than the Minimum Detectable Activity were detected in water samples (MDA) for Pb{sup 212}, Bi{sup 214}, Pb{sup 214}, Ac{sup 228}, but situated under values foreseen in drinking water. Distribution of Uranium As results of the Uranium determination, values higher than 0,004 mg/l (4 ppb) were detected, values that represent the average contents in the underground water. The higher values, 2-3 times higher than background, were detected in the water from the drillings F15, F12, F5, F13, drillings located between RWTP